Category: KSEEB Important Questions

Karnataka 2nd PUC Economics Important Questions Chapter 2 Theory of Consumer Behaviour

Very Short Answer Type Questions

Question 1.
What do you mean by utility?
Answer:
Utility is the want satisfying power of a commodity.

Question 2.
How is total utility derived from marginal utilites?
Answer:
Total Utility is the sum total of marginal utilities ofvarious units of a commodity.

Question 3.
State the law of equi- marginal utility?
Answer:
It states that a consumer gets maximum satisfaction when the ratio of the marginal utilities ofthe goods and their prices i.e. Mux / Px = MUy/Py

Question 4.
What will you say about Mu the TU is maximum?
Answer:
MU is zero then TU is maximum.

Question 5.
Give the reason behind a convex indifference curve?
Answer:
Diminishing marginal rate of substitution.

Question 6.
Give the formula for calculating the slope of the budget line?
Answer:
It is equal to the ratio of the prices of the two comodities i.e Px / Py.

Question 7.
Suppose a consumer’s preference are monotonic. What can you say about mis preferece ranking over the bundles (10,10), (10,9) & (9,9)?
Answer:
Consumer will monotonically Prefer bundle (10, 10) to (10, 9) and (9, 9) and also Prefer bundle (10, 9) to (9, 9)

Question 8.
A rise in the income of the consumer leads to a fall in the demand for commodity ‘x’ What type of good is commodity ‘x’?
Answer:
Inferior good.

Question 9.
What do you mean by a substitute and complementary goods? Give two examples each.
Answer:
Substitute goods are those goods which can be used in place of each other.
Ex: Tea and coffee.

Question 10.
Mention one factor that causes a left ward shift of the demand curve?
Answer:
Fall in income of a consumer.

Question 11.
What causes a movement along the demand curve of a commodity?
Answer:
When the price of a commodity changes and other factors remain constant, there will be movement along the demand curve.

Question 12.
Draw a demand curve with unitary elasticity?
Answer:

Question 13.
Define Price elasticity of demand?
Answer:
It refers to the degree of responsiveness of quantity demanded to change in price.

Question 14.
What is the indifference curve?
OR
Define the Indifference curve?
Answer:
An Indifference curve is a set of combinations of the two commodities which offer a consumer the same level of satisfaction

Question 15.
The consumer prefers more goods to less, what will be the slope of the indifference curve in that case?
Answer:
In that case, the indifference is downward sloping.

Question 16.
When is the indifference curve convex to origin in that case?
Answer:
In that case, the indifference curve is convex to origin when the consumer prefers average bundles to extreme.

Question 17.
What is the marginal rate of substi-tution?
Answer:
The rate at which the consumer can substitute good -1 for good -2 and be different is called marginal rate of substitution (MRS)

Question 18.
What does the word equilibrium mean?
OR
Give the meaning of equilibrium?
Answer:
Equilibrium means a position of rest or a situation of no change.

Question 19.
What does consumer’s equilibrium refer to?
Answer:
Consumer’s equilibrium refers to a situation when he spends his given income on purchase of commodity to (or combination of goods) in such a way that yield him maximum satisfaction and he feels no urge to change.

Question 20.
Give the meaning of demand?
Answer:
Demand is the quantites demanded of particular goods and consumer’s willingness to buy it at a particular price with in a given period of time.
OR
Demand refers to desire towards commodity by an individual coupled with willingness and abilities to buy.

Question 21.
Name the determinants of demand?
Answer:
The determinants of demand are:

1. Price of a product
2. Price of related goods
3. Income of consumer
4. Taste & preferences of the consumer

Question 22.
What is the law of demand?
Answer:
The law of demand states that when other remaining constant the quantity demanded will increase with fall in price and decrease with the rise in price.

Question 23.
Define an indifference Map?
Answer:
An Indifference map is a collection of indifference curves corresponding to differenat levels of satisfaction. –

Question 24.
In which market form the demand curves of a firm is perfectly elastic?
Answer:
In a perfectly competitive market, the demand curve of a firm is perfectly elastic.

Question 25.
Why is the demand for water inelastic?
Answer:
Demand for water is inelastic because water is an essential and it is abundant.

Question 26.
Give the meaning of marginal revenue?
Answer:
Marginal revenue means the change in the total revenue which results from the sale of one or more unit of a commodity.

Question 27.
Define production function?
Answer:
Production may be defined as the functional relationship between physical outputs and physical inputs of a commodity.

Question 28.
Define marginal utility?
Answer:
Marginal utility can be defined as an addition to total utility due to increse in one unit of a commodity.

Question 29.
What happens to total expenditure on a commodity when its price falls and its demand is price elastic?
Answer:
Total expenditure will increase.

Question 30.
What causes and upward movement along a demand curve?
Answer:
Increase in the price of a commodity causes an upward movement along the demand curve.

Question 31.
What is market demand?
Answer:
Market demand may be defined as the total quantity of commodity which all the buyers in the market are willing to buy at different prices in a given period of time.

Question 32.
What does decrease in supply refers to?
Answer:
Decrease in supply means that the sellers sell less quantity of a good at its existing price.

Short Answer Type Questions

Question 1.
Qd = 20-2p is a demand equation.
Identify independent variable, dependent variable, constant and co-efficient in it. ,
Answer:
From the equation Qd = 20 -2p
P → Independent variable
Qd → Dependent variable
20 → Constant
2 → co-efficient

Question 2.
Qd = 20-2p is demand function of onion. Suppose the onion in the market is Rs. 10 per kg. Calculate the quantity demanded?
Answer:
When Price is 10
i.e P is 10
Qd = 30 – 2 (p)
Qd = 30 – 2 × 10
Qd = 30 – 20
Qd = 10
The quantity demanded will be 10 kgs.

Question 3.
Imagine there are only two consumers in a market. They are x and y. Their demand for a good is given as follows Calculate the market demand for the good & draw the market demand curve.
Answer:

Question 4.
Differentiate ‘total utility’ and ‘marginal utility’?
Answer:
Total Utility:
Total utility refers to the utility which will be obtained by consumption of all units of the commodity.
The marginal utility is the net addition made to the total utility by consuming extra unit of a commodity.

Question 5.
What is the difference between utility and satisfaction.
Answer:

Utility	Satisfaction
1. Utility is the satisfying power of a commodity, before consumption.	1. Whereas a consumer get satisfaction only after consumption.
2. Utility is an ‘Expected Satisfaction’.	2. Whereas it is Realized Satisfaction.

Question 6.
What are the properties of a Budget line?
Answer:
The properties of a Budget line are:

• The Budget line always slopes downwards from left to right.
• Bundles, whose cost is exactly equal to consumers’ money income lie on the Budget line.

Question 7.
What is the relationship between marginal utility and total utility?
Answer:
Relationship between marginal utility and total utility!

1. Total utility increases as long as marginal utility is positive.
2. Total utility is maximum when marginal utility is zero.
3. The total utility starts declining when marginal utility becomes negative.

Question 8.
What does the law of diminishing marginal utility state?
Answer:
The Law of diminishing marginal utility simply tells us that we obtain less and less marginal utility from the successive units of a commodity as we consume more and more of it.

Question 9.
What do you mean by
(i) Intial utility
(ii) Marginal utilitey
(iii) Total utility?
Answer:
(i) Initial utility:
Initial utility refers to the utility that is derived by consuming the first unit of a commodity. ‘
For Example: Having a first cup of tea to reduce fatigue is the initial utility.

(ii) Marginal utility:
The marginal utility can be defined as the addition to the total utility obtained from the consumption of one more unit.
For Example, The marginal utility of the second unit of a good is the change in total utility resulting from consuming the second unit of the good.
MUn = TU_n – TU_n-1

(iii) Total utility
Total utility is the amount of utility or satisfaction that a consumer gains from consuming a given amount of goods or services over a period.
For example, A person consumes five units of commodity and derives U₁ U₂, U₃, U₄, U₅ utility from the successive units of a commodity, then the total utility will be
TU = U₁ + U₂ + U₃ + U₄ + U₅

Question 10.
When Marginal utility is zero, then utility is maximum prove it with the help of a table.
Answer:
With the help of the following table, we can deduce that total utility is maximum when marginal utility is zero.

From the above table we come to know that when a consumer, consumes 5 oranges, the marginal utility is zero and at this level the total utility is maximum i. e. 40

Question 11.
Write down the assumptions of law of diminshing marginal utility?
Answer:
Assumptions of law of diminishing marginal utility:

1. The units of consumption must be in standard units. eg: a cup of tea, a bottle of cool drink, an apple etc.
2. All the units of the commodity must be identical in all aspects like taste, quality, colour & size.
3. The units of the commodity should be used continuously if there is any interval between the consumption of two units, then the law will not operate.
4. Consumer must be rational. It means, consumer should maximise utility.
5. The price ofhe commodity consumed and its substitutes must remain constant.
6. Utility can be measured in cardinal numbers like 1,2, 3, 4,…. n units.
7. Consumer should be an ordinary person this law is not applicable to extraordinary _ persons.

Question 12.
Write any four limitations of the law of diminishing marginal utility?
Answer:

1. The Law is not applicable to rare collections. Ex: ancient coins, stamps etc
2. It is not applicable in case of Prestigious goods Ex: gold, diamonds etc.
3. It does not apply to knowledge, art and innovations.
4. The law is not applicable to money. The marginal utility of money declines with richness but never falls to zero.

Question 13.
Explain the importance of Law of diminishing marginal utility?
Answer:
The importance of the Law of diminishing Marginal utility:

1. By purchasing more units of a commodity, the marginal utility decreases, due to this behaviour, the consumer cuts his expenditure on that commodity. It helps to utilise the resources economically.
2. In the field of public finance’, this law has a practical application as the principle of taxation is based on this law.
3. This law is the base to ther economic laws such as law of demand, elasticity of demand, consumer surplus, the law of substitution etc.
4. The theory of value is based on this law. The value of a commodity falls with an increase in the supply of that commodity. This forms the basis for determining prices.
5. This law is the basic for the socialist please for an equitable distribution of wealth.

Question 14.
Differentiate between Substitute goods & complementary goods?
Answer:

Substitute Goods	Complementary Goods
1. These are those goods which can be used in place of each other to satisfy a given want. Tea & coffee are substitute goods.	1. These are those goods which are used together to satisfy a given want. They are demanded jointly, i.e. their consumption goes together. Car and petrol are complementary goods.
2. In case of substitute goods there is direct relationship between the demand for the commodity and price of its substitute i.e, increase in price of a commodity will increase demand for its substitutes and decrease in price of the commodity will decrease the demand for its substitutes.	2. In case of complementary goods, there is inverse relationship between the demand for a commodity and the price of its complementary goods. For example: Rise in the price of petrol will lead to fall in demand for scooter and fall in price of petrol will lead to rise in demand for scooter.

Question 15.
How is the market demand curve derived from the individual demand curves?
Answer:
The Market demand curve i.e, the demand curve of a product by all individuals taken together in economy is obtained by horizontally summing up the demand curves across consumer’s or household. Below market demand curve has been drawn with the help of individual demand curves.

Question 16.
DifFerntiate between shift of the demand curve and movement along the demand curve?
Answer:
Shift of demand curve:
1. Shift of demand curve takes Place due to changes in factors other than the price such as income of the consumer.

2. Shift of demand curve is of two types

1. Left side &
2. Right side.

3. In case of shift of demand, more is demanded at the same price.

4. Factors other than price change.

5. Shift of demand curve has been shown below diagrammatically.

1. Movement along the demand curve is caused due to change in price alone.
2. Movement along the demand curve is of two types:
   (i) Upward movement
   (ii) Downward movement.
3. In case of movement along the demand curve, more is demaded at a lower price and vice -versa.
4. Factors other than price remain constant.
5. Movement along the demand curve has been shown below diagramatically.

Question 17.
Explain how rise in income influence demand for a good?
Answer:
Effect of change in income of the demand for a commodity.

1. Increase in income leads to increase in demand for normal goods and vice versa.
2. increase in income leads to decrease in demand for inferior goods and vice versa.
3. The demand for necessary goods increases upto a certain limit with the increase in income and after that limit, the increase in income has no effect on its demand.
4. The demand for consumer goods increases with the increase in income.

Question 18.
Find two difference between Budget time & Budget set?
Answer:
Budget line:

• The combination of two goods that a consumer purchases depend upon the income and price of two goods.
• Budget line is a Locus of different combination of the two goods which the consumer consumes.

Budget set:

• A Budget set is a collection of all Bundles available to a consumer at the Prevailing market price at a given level of income.
• Budget set includes all the Bundles with a total income.

Question 19.
What are the difference between cardinal & ordinal approach to utility analysis?
Answer:

Cardinal Approach	Ordinal Approach
1. The Cardinal approach is known as utility approach.	1. Ordinal approach is also known as Indifference approach.
2. The cardinal approach is also collected as traditional and Marshallian approach.	2. The ordianl approach is described as Hicksian approach.
3. According to cardinal concept utility is quantitatively measureable	3. According to ordinal concept, utility cannot be Quantitatinely measurable.
4. In cardinal utility concept is is possible to measure utilites in cardinal numbers such as 1, 2, 3, 4 etc.	4. And in ordinal utilites concept, utility connot be measured by numbers, but utility can be expressed by giving ranks or order such as I, II, III, IV etc.

Long Answer Type Questions

Question 1.
Explain the concept of ‘Budget Bne’and ‘Budget set’ with an example?
Answer:
Budget line:
The budget line is the combination of two goods that a consumer purchases depends upon the income (consumer budget) and the prices of the two goods.
Ex: Let us understand the concept of Budget with help of example.
Suppose, a consumer has an income of Rs. 20 and wants to spend it on two commodities x and y which are

Priced at the 10 each Now the consumer has three options to spend the entire income.

1. Buy 2 units of x
2. Buy 2 units of y
3. buy 1 unit of x and 1 unit of y.

Budget Set:
Is a collection of all bundles available to a consumer at Prevailing market price at a given level of income. Budget set is also known as ‘opportunity set’
Ex: Suppose a consumer has a budget of Rs. 20 to be spent on two commodities. Apple (A) and Banana (B). If apples are priced as Rs. 4 each and Bananas at Rs. 2 each, then the consumer can determine the various Options which form the budget line.

1. The possible options of spending income of Rs. 20 are given below

Question 2.
Explain any five properties of Indifference curves?
Answer:
The properties of indifference curve:
1. A higher Indifference curve represents a higher level of satisfaction than a lower Indifference curve

2. An Indifference y curve cannot be a downward sloping straight line. If it so as shown in the diagram then the MRS will remain constant. This is unrealistic.

3. An Indifference curve cannot be a vertical line or horizontal line. If is more so, it would be contrary to the principles of the Indifference curve.

4. An Indifference curve must always be convex to the origin and not concave.

5. An Indifference curve cannot have a bulge as below.
If an Indifference curve has a bulge as shown in the diagram, it is clear f that the MRS is not diminishing constantly. It means the consumer is ° behaving erratically.

Question 3.
Explain the law of diminishing marginal utility with schedule and diagram?
Answer:
The Law of diminishing marginal utility simply tells us that we obtain less and less marginal utility from the sucessive units of a commodity as we consume more and more of it.


In the diagram units of apples consumed are measured along OX axis and the utility along OY axis.

As it is clear in the diagram when the consumer consumes first apple, he gets a total utilities of 8 units and the marginal utility also become 08 units. The second apple gives him 5 units of utility which is less than that of the first apple. If he continues to the 3rd and 4th units of apples the marginal utility diminishes to 3 and 4 units respectively. When he consumes the fifth (5th) his total utility remains at 18 units (which is maximum) and the marginal utilitiey becomes zero (0). If he consumes the sixth (6th) apple, the marginal utility becomes negative and total utility starts diminishing.

Question 4.
Explain the Indifference curve and Indifference map with help of schedule and diagrams.
Answer:
Indifference curve shows the different combinations of two commodities in which consumers get equal satisfaction.
It explains consumer behaviour in terms of his Preferences or rankings for different combinations of two goods, say x and y. An indifference curve is drawn from the indifference schedule of consumer. The latter showes the various combinations of the two commodities such that the consumer is indiffrent to those combinations. “An indifference schedule is a list of combinations of two commodities, preferring none of any other”


In the diagram Biscuits is represented on the x-axis. And Banana’s on the y axis. It can be understood that when the number of biscuits increase, the number of banana’s will decrease so that the level of satisfaction is the same for all the combinations therefore, you are different between the combinations A, B, C, D & E.

Indifference Map:
A group or a set of Indifference Map curves for two commodities showing different levels of satisfaction is called Indifference Map.

In the Indifference Map, it should be clearly understood that a higher indifference curve denotes a higher level of satisfaction and a lower indifference curve represents lower level of satisfaction.

In the diagram, IC₄ gives a higher level of satisfaction compared to IC₃, IC₂, IC₁ and at the same time IC₁ yields lower level of satisfaction Compared IC₂, IC₃, IC₄

Question 5.
Explain consumer’s equilibrium through indifference curve analysis?
Answer:
An indifference depicts the choice and priority of a consumer. The budget line shows the ability to pay choice and priority can be achieved only when there is affordability. Therefore, In order to achieve consumer’s equilibrium that maximises, utility. We have to determine the combination of goods that can be purchased within a certain amount of budget.

The consumer’s equilibrium can be illustrated with help of a diagram.

In the diagram there are four indifference curves IC₁, IC₂, IC₃ and IC₄ and a budget line PQ. Which of the points from A to D is and optimal utility maximizing optimum choice willbe.
1. Suppose point B is optimal?
No. Ais better than B since A is on a higher indifference curve. The consumer has to choose A, since ‘A’ on the Budget line.

2. Suppose point ‘C’ is optimal?
No. Because, Both B and G are on the same indifference curve, therefore, B is as good as c. However ‘A’ Better than ‘B’ and ‘C’

3. Suppose point ‘D ’ is optimal?
No. ‘D’ is on a higher indifference curve than any of other Baskets, Ato C. It, therefore produces the highest level of utility. However, the consumer cannot ‘D’ since it lives outside the budget line therefore, D is not an optimal choice.

4. Suppose point ‘A’ is optimal?
Yes. ‘A’ is the only combination that gives the maximum utility. All other points that lie on or below the budget line give higher or lower levels of utility. At point A, the indifference curve just touches the budget line and equilibrium is achieved at that point.

Thus we can say that the consumer is in the equilibrium position when the price line is target to the indifference curve.

Question 6.
Explain the law of demand with the help of demand Schedule and demand curve?
Answer:
The Law of demand states that when the price of a good decrease, the demand for it increases and when the price increases, the demand for the good decreases.

Demand Schedule:
The law of demand can be explained with the help of a demanding schedule.

Price per unit in Rs.	Quantity demanded in units.
1	10
2	8
3	6
4	4
5	2

In the diagram the price in rupees is represented on Y-axis and the Qantity demanded on (x) Axis. If the price of orange is Rs. 1 per unit, 10 oranges are demanded. If the price of orange increases Rs.2, Rs.3, Rs. 4 and Rs. 5 per unit the number of oranges demanded decreases to 8, 6, 4 and 2 units respectively. Thus this proves that there is an inverse relation between the price and quantity demanded

Question 7.
Classify the price Elasticity of demand and explain them with diagram?
Answer:
The degree of price elasticity of demand varies from one good to another on the basis of this, the price elasticity of demand can be calssified as follows.
1. Perfectly elastic demand
It refers to a situation where the slightest change in the price of a commodity leads to infinite or rapid change in quantity demanded. In this case
E_p = \(\frac{\infty}{0}\) = ∞ (∞ is an infinite sign)

Perfectly inelastic demand:
Demand is said to be perfectly inelastic when a substantial change in the price does not lead to any change in demand. In this case. Ped = 0 or E_p = 0 Here the demand curve (DD) is vertical.

Relatively elastic demand:
Demand for a commodity? is relatively elastic when a change in price If ads to more proportionate change in quantity demanded.

ex: If the price Changes by 10 percent, then the change in demand is 15 percent.

Here the .demand curve (DD) is flatter.

Relatively inelastic demand
Demand for a commodity is relatively inelastic when a change in price causes a less than proportionate change in the quantity demanded in this Ped < 1.
Ex: When a 10, per cent change in price causes a per cent change in demand
In this case Ped < 1

Unitary elastic demand
Price elasticity of demand is unity when the change in demand is exactly proportionate to the change in price.
In this case Ped = 1

Ex: When a 10 per change in price causes a 10 percent in demand. Here the demand curve (DD) takes the shape of a rectangular hyperbola.

Exercises

Question 1.
What do you mean by the budget set of a consumer?
Answer:
The budget set of a consumer means the collection of all bundles that consumers in an economy can buy with their incomes at the prevailing market price.

Question 2.
What is budget line
Answer:
The Budget line shows the particular combination of two goods that a consumer can buy with a given money income when price is constant.

Question 3.
Explain why the budget line is downward sloping?
Answer:
The budget line is downward sloping because if the consumer wants to consume an extra unit of one commodity, he has to give up some amount of other commodity.

Question 4.
A Consumer wants to consume two goods. The price of two goods are Rs. 4 and Rs. 5 respectively. The consumers income is Rs. 20.
1. Write down the equation of the budget line.
2. How much good – 1, can the consumer consume if she spends her entire income on that good?
3. How much good-2, can she consume if she spends her entire income on that good?
4. What is the slope of the budget line which is as follows.
Answer:
1. The equation of the budget line is as follows
P₁ x₁ + P₂ x₂ = M
Solving the above exaple with the equation:
4x₁ + 5x₂ = 20
Price of X₁ commodity → 4 Rs.
Price of X₂ commodity → 5 Rs.
The Income of consumer (M) → 20Rs.

2. M = P₁x₁ + P₂x₂
20 = 4x₁ +0
4x₁ = 20
x₁ = \(\frac{20}{4}\) = 5 units

The consumer can consume 5 units of commodity-1 if she spends her entire income on that good.

3. M = P₁x₁ + P₂ x₂
20 = 0 + 5x₂
5x₂ = 20
x₂ = \(\frac{20}{5}\) = 4 units
The Consumer can consume 4 units of commodity 2 if she spends his entire income on that good.

4. The slope of the budget line is
M = \(\frac{P_{1}}{P_{2}}=\frac{4}{5}\) = 0.8

Question 5.
How does the budget line change if the consumer’s income increases to Rs. 40, but the prices remain unchanged?
Answer:
The budget line will shift outward i.e. to its right as shown in the diagram. The dotted line is the new budget line.

Question 6.
How does the budget line change if the Price of good -2 increases by a rupee-1 but the price of good -1 and the consumer’s income remain unchanged?
Answer:
There will be an outward shift of budget line meeting OX – axis due to the fall in the Prices of good -2 as shown in the diagram.

Question 7.
What happens to the budget set if the prices of both goods as well as the income doubles.
Answer:
There will be no change in the budget set if the prices of both goods as well as the income doubles.

Question 8.
Suppose a consumer can afford to buy 6 units of goods-1 and 8 units of good – 2, if he spends his entire income. The prices of the two goods are Rs. 6 and Rs. 8 respectively. How much is the consumer’s income?
Answer:

Hence consumer’s income is Rs. 100.

Question 9.
Suppose a consumer wants to consume two goods which are available only in the interger units. The two goods are equally priced at Rs. 10 and the consumer’s income is Rs. 40.
(i) Write down all the bundles that are available to the consumer.
(ii) Among the bundles that are available to the consumes identify those that cost have exactly Rs. 40.
Answer:
1. All bundles available to the consumers are as follows:
(0,0), (0,1), (0,2), (0,3), (0,4), (1,0), (1,1), (1,2), (1,3), (2,0), (2,1), (2,2), (3,0), (3,1) and (4,0)

2. Bundles which cost exactly Rs. 40 are as follows:
(0,4), (1,3), (2,2), (3,1) & (4,0)

Question 10.
What do you mean by monotonic preferences?
Answer:
It means that a rational consumer always prefers a commodity as it offers him a higher level of satisfaction.

A consumer’s preferences are monotonic only if it is between any two bundles, the consumer prefers the bundle which has more of at least one of the goods and no less of the other good as compared to the other bundle.

Question 11.
If a consumer has monotonic preferences can she be indifferent between the bundles (10,8) and (8,6)
Answer:
No, she cannot.

Question 12.
Suppose a consumer’s preferences are monotonic. What can you say about her preference ranking over the bundles (10,10), (10,9) and (9,9)
Answer:

Bundles	Ranking over the bundles
(10,10)	Best
(10,9)	Second
(9,9)	Third

Question 13.
Suppose your friend is indifferent between the bundles (5,6) and (6,6). Are the preferences of your friend monotonic?
Answer:
No.

Question 14.
Suppose there are two consumers in the market for a good and their demand functions are as follows:
d1 (p)=20-p, for any price less than or equal to 15, and d1(p)=0 at any price greater than 15.
d (p)=30-2p for any price less than or equal to 15, and d^p)^) at any Price greater than 15. Find out the market demand Function.
Answer:
A – Consumer – d₁(P) = 20 – P → when P< 15,
d₁(P) = 0 when P>15 ………..(1)
B – Consumer – d₂(P) = 30 – 2P → when P<15, d₁ – (P) = 0 when P >15 ………(2)
Market demand – d_m = 50 – 3P, is the market demand we get by adding both equations (i) & (ii).

Question 15.
Suppose there are 20 consumers a good and they have identical demand functions. d(p) = 10 – 3 p for any price less than or 10 equal \(\frac{10}{3}\) and d₁(p) = 0 at any greater 10 than \(\frac{10}{3}\) What is market demand function?
Answer:
d_m(p)= (10-3p) 20 for any price less than 10 or equal to \(\frac{10}{3}\) and d1(p) = 0 for any price greater \(\frac{10}{3}\).

Question 16.
Consider a market where there are just two consumers and suppose their demands for goods are as follows, calculate the market demand for the good.


The market demand for the good:
Answer:
d₁ + d₂ = d_m

Question 17.
What do you mean by a normal good?
Answer:
Normal goods are those goods whose demand increases with increase in income and vice versa.

Question 18.
What do you mean by an inferior good? Give Some examples?
Answer:
A good for which the demand decreases with an increase in the income of the consumer is called an inferior good.
Ex: Pearl millet (sale), finger millet (ragi)
etc.

Question 19.
What do you mean by substitute goods? Give example of two goods which are substitutes of each other V
Answer:
Goods that are used as alternatives to satisfy a particular need are called substitute goods.
Ex : Goods like Tea & coffee, Diesel & gas etc.
OR
When the price of a good increase, the demand for its substitute good also increases.

Question 20.
What do you mean by complements? Give examples of two goods which are complements to each other?
Answer:
Goods which are consumed together to satisfy a want are called complementary goods.
or
When the Price of a good increases, the demand for its complementary good decreases.
Ex: Scooter & Petrol, Tea & sugar, Pen & ink etc.

Question 21.
Explain Price elasticity of demand?
Answer:
Price eleasticity of demand refers to the change in quantity demanded due to the change in the Price of commodity.

It can be calculated by the formula.
ped = \(\frac{\text { Percentage change in demand }}{\text { Percentage change in price }}\)
or
Ped = \(\frac{\Delta q}{\Delta P} × \frac{P}{q}\)

Question 22.
Consider the demand curve for a good. At Price Rs. 4 the demand for the good is 25. Suppose price of the good increases to Rs. 5 and as a result the demand for the goods falls to 20 units. Calculate price elasticity.
Answer:

Price	Quantity demanded units
4	25
5	20

ΔP = 5 – 4 = 1Rs.
Δ q = 25 – 20 = 5 units
P = 4 Rs
q = 25

Ped = 0.8

Question 23.
Consider the demand curve D (p)= 10-3p. What is the elasticity at price \(\frac{5}{3}\)
Answer:
We know that a linear demand curve is expressed as
q = a – b P
Here D = 10 – 3 P
Hence, a = 10
b = 3
P = \(\frac{5}{3}\)

Hence, eleasticity of Price = -1

Question 24.
Suppose the Price Elasticity of Demand for a good is 1.2. If there is a 5% increase in the price of the good, by what percentage will the demand for the good go down?
Answer:
Ped = \(\frac{\text { Percentage change in demand }}{\text { Percentage change in price }}\)
Substituting the value we get,
0.2 = \(\frac{\text { Percentage change in quantity demand }}{5}\)
or, Percentage change in quantity demanded . = 0.2 × 5 = 1 (one)

Question 25.
Suppose the Price elasticity of demand for a good is -0.2. How will the expenditure on the good be affected if there is 10% increase in the price of the goods?
Answer:
Here the PEd = 0.2, i.e. Ed < 1. If Ed < -1 then (1 + Ed)< 0 and hence E has the same sign as Δ P Here Δ P has plus sign, so Δ E will have plus sign. Hence, expenditure will increase.

Question 26.
Suppose there was a 4% decrease in the price of a good and as a result. The expenditure on the good increased by 2%. What can you say about the elasticity of demand?
Answer:
Here, change in price (decrease) and change in expenditure is (increase) go in the opposite direction. Hence Ed > 1.

2nd PUC Economics Important Questions with Answers

Karnataka 2nd PUC Economics Important Questions Chapter 1 Introduction to Micro Economics

Very Short Answer Type Questions

Question 1.
What is economics about?
Answer:
Economics is the study of the problem of choice arising out of scarcity of resources that have alternative uses.

Question 2.
Define scarcity?
Answer:
Scarcity means a shortage of resources in relation to their demand.

Question 3.
What is an economy?
An economy is a system by which people get their living

Question 4.
Define central problem?
Answer:
The central problem is concerned with the problems of choice or the problem of resource allocation

Question 5.
What do you mean by positive economic analysis?
Answer:
It deals with what is or how an economic problem facing an economy is solved. It analyses the cause of effect relationship

Question 6.
What do you understand by normative economic analysis?
Answer:
Normative economics analysis deals with What ought to be or How an economic problem should be solved.

Question 7.
Give one reason which gives rise to the economic problems?
Answer:
Scarcity of resources that have alternative uses

Question 8.
Name the three central problems of an economy?
Answer:
The three central problems of an economy are:

• What to produce
• How to produce
• For whom to produce

Question 9.
What does the opportunity cost?
Answer:
It is the cost of the next best alternative forgone.

Question 10.
Why there is a need for economizing resources?
Answer:
Resources are scarce in comparison to their demand therefore it is necessary to use resources in the best possible manner without wasting them.

Question 11.
Why PPC is concave to the origin?
Answer:
PPC is concave to the origin because of increased marginal opportunity cost.

Question 12.
Define marginal rate of transformation?
Answer:
MRT is the ratio of a unit of one good sacrificed to produce one more unit of other goods
MRT = Δy / Δx

Question 13.
What does a point inside the PPC indicate?
Answer:
Any point inside the production possibility curve indicates the underutilization of resources.

Question 14.
Give two examples each of Microeconomics & macro-economics?
Answer:

• Micro-economics- Individual demand, individual supply
• Macro-economics- Aggregate demand, aggregate supply

Question 15.
What does a rightward shift of PPC indicates?
Answer:
It indicates

• Growth of resources
• Improvement in technology

Question 16.
What is meant by economising resources?
Answer:
It means wisely use of resources.

Question 17.
What do you mean by unlimited wants?
Answer:
It means that there is no limit to human wants (needs) They are unlimited (infinite)

Question 18.
Name any two branches of economics?
Answer:
The two branches of economics are:

1. Microeconomic
2. Macroeconomics

Question 19.
Give the name of different definitions of economics given by different economists?
Answer:
The definitions of economics are:

1. Wealth definition- Adam Smith
2. Welfare definition – Pro. Alfred marshall
3. Scarcity definition- Lionel Robbins
4. Growth definition- Paul A. Samuelson

Question 20.
What are the basic economic activities of the economy?
Answer:
The basic activity of the economy is

• Production
• Consumption
• Exchange of goods

Short Answer Type Questions

Question 1.
Explain the problem of “ What to produce” with the help of an example? What to produce:
Answer:
The first central problem of an economy in which goods and services should be produced to satisfy the human wants of the people, this problem arises due to the fact that means are scarce in relation to the wants.

We can produce a number of combinations such as producer goods and capital goods. We have to decide whether consumer goods are to be produced or capital goods. After deciding what goods should be produced, we will decide the quantity of each good le. how much of consumer goods and how much of producer goods are to be produced

If a society produces more consumer goods, it will have fewer resources to produce producer goods, on the production possibility curve, the problem ‘What to produce’ is the problem of choosing the points on the curve (A, B,C and D)

Question 2.
What is the production possibility frontier?
Answer:
It is a boundary line that shows a maximum of two goods that can be produced with the help of given resources and technology at a given period of time.

Ex: An economy can produce two goods say rice or oil by using all its resources The different combinations of office and oil are as follows:

Question 3.
Why does an economic problem arise? Explain the problem of ‘How to produce’?
Answer:
An economic problem arises due to unlimited wants & limited resources which have alternative uses.
How to produce:
It is a problem of choice of technique There are two types of techniques of production

1. The capital-intensive technique (using more capital and less labour) and
2. Labour intensive technique (using more labour in relation to capital).

An economy has to decide as to what technique is to be used in a given industry to have the least possible cost to produce each unit of commodity or service, It is called the most efficient technical method of production.

Question 4.
Explain the three basic economic activities that take place in an economy?
Answer:
The three economic activities that take place in an economy are:

1. Production
2. Consumption
3. Capital formation

1. Production: It is an activity that creates or adds utility to goods and services. utility of goods can be created or added by changing the shape, place etc.

2. Consumption: Using up of goods and services for satisfying the human needs, with the consumption the utility of goods and services decreases or destroyed.

3. Capital formation (Investment): It is the addition to the capital stock of the economy in a given period, The surplus of production over consumption in an accounting year is also defined as capital formation.

Question 5.
Give the properties of the production possibility curve?
Answer:
1. It slopes downward to the right: The downwards slope or negative slope of the production po ssibility curve shows that if more of one good is to be produced then loss of other goods will be produced

2. It is concave to the point of origin: Production possibility curve has a concave slope towards point of origin, The concave slope shows that more and more unit of one commodity shall have to be sacrificd to produce .additional units of another commodity

Question 6.
An economy produces two goods:
Answer:
Chocolates and Biscuits. The following tables summarise its production possibilities. Calculate the marginal Opportunity cost of chocolates at various combination

Chocolates (in thousands)	Biscuits (in lakhs)
0	90,000
1	80,000
2	68,000
3	52,000
4	34,000
5	10,000

Question 7.
Explain any two features of a centrally planned economy?
Answer:
Two features of a centrally planned economy are as follows:

1. Ownership of means of production: In a centrally planned economy, all factor factors of production like land, man-made resources and natural resources are owned by state.
2. Motive: In a centrally planned economy social welfare in the primary motive of all activities

Question 8.
Identify which of the following are the subject matter of microeconomics or macroeconomics?
(i) General price level
(ii) Price determination of a commodity
(iii) National income
(iv) Supply by a firm
(v) Iron- steel industry
(vi) Government budget
Answer:
(a) Subject matter of microeconomics:

• Price determination of a commodity
• Supply by a firm
• The iron-steel industry, because they are individual units.

(b) Subject matter of macro-economics

• General price level
• National Income &
• Government budget, because they are aggregate units

Long Answer Type Questions

Question 1.
How are central problems solved in different economics?
Answer:
There are three different economies

1. Market economy
2. Centrally Planned economy
3. Mixed economy

Central problems are solved differently in different economies as it is clear from the following details:

1. Market economy:
In a market economy, those goods are pro¬duced which offer high prices and high profits to the producer.
The producer will use that technique of production which keep the cost of production as low as possible
The producer will produce the goods for

the rich who can afford high prices, a poor section of the society are generally ignored.
In short all decisions are related to the maximisation of profits.

2. Centrally Planned economy:
In a centrally planned economy decisions regarding ‘What to produce’,” How to pro¬duce” and Whom to produce are taken by a government or a central authority appointed by the government of the country. All decision are taken with a view to maximising social welfare.

3. Mixed economy:
In mixed economy, decision regarding ‘What, how and for whom to produce are taken on the basis of market forces as well as on the basis of social consideration.

Exercises

Question 1.
Discuss the central problems of an economy
OR
How does an economic problem arise?
Answer:
We know that available resources are -limited in relation to their requirement. Therefore, it is important to economise on their use.

The problem of resource allocation in the economy assumes the following there forms in an economy.
The major central problems are as follows:

1. What to produce? (Problems of choice)
2. How to produce? (Problems of choice of technique)
3. For whom to produce (Problems of distribution)

1. What to produce:
The first central problem of an economy is to decide what to produce, the problem of what to produce is the problem of choice between commodities and this problem arises due to scarcity of resources.

2. How to produce:
The next problem of an economy is to decide as to how to produce goods and services ‘ How to produce’ is the problem of choice of technique” since resources are limited, it becomes necessary to choose a technology

3. For whom to produce:
The third basic problem of an economy is to decide for whom the goods shall be produced. The problem “ For whom to produce” is a problem of distribution of goods and services among the members of societies.

Question 2.
What do you mean by the production possibilities of an economy?
Answer:
Production possibilities mean that an economy can produce various combinations of the two goods with its limited resources and technology.

Question 3.
What is a production possibility frontier?
Answer:
The production possibility curve is called the production possibility frontiers and gives the combination of two goods that can be produced when the resources of the economy are fully utilised
OR
The curve gives the maximum amount of one commodity (ex: com) that can be produced in the economy for any given amount of other commodity (ex: cotton) and vice versa, this curve is called the production possibility frontier.

Question 4.
Discuss the subject matter of economics?
Answer:
Subject matter of economics is the study of different activities which are directed towards the maximisation of satisfaction of an indivdual and maximisation of social welfare at the level of the country as a whole.

Question 5.
Distinguish between a centrally planned economy and market economy?
Answer:
1. Centrally planned economy:
In a centrally planned economy or socialist economy, here all the economic activities are controlled and managed by the central government rather than the private business.

In such economies the government takes decision about allocation of resources and the government decides What to produce, How to produce and What prices are to fixed

The countries like North Korea, Cuba, China & Vietnam etc., follow a centrally planned economic system.

2. Market economy:
Market economy or capitalistic economy is an economy where the private sector plays important role in taking economic decision and allocation of resources

In market economics, private individuals own the factors of production Here profit is the ‘Sole motive’ and there will be no interference by the government in the economic activities of the economy.

The countries like America, Japan, Australia etc., follow a market economy.

Question 6.
What do you understand by positive economic analysis?
Answer:
It deals with what is (or) how an economic problem facing an economy is solved. It analyses the “ cause & effect relationship”

Question 7.
What do you understand by normative economics analysis?
Answer:
The normative economic analysis deals with what ought to be (or) how an economic problem should be solved

Question 8.
Distinguish between micro-economic & macroeconomic?
Answer:

Micro-economic	Macro-economics
1. It studies individual economic unit	1. It studies aggregate economic unit
2. It deals with the economic activities of a firm or an industry	2. It deals with the aggregates like aggregate demand, supply, aggregate employment, national income, expenditure etc.
3. Its central problem are price determination & allocation of resources	3. Its central problem is the determination of level of income and employment in the economy
4. Demand and supply are the tools of micro-economic analysis	4. Aggregate demand and aggregate supply are the main tools of analysis.

2nd PUC Economics Important Questions with Answers

Karnataka 2nd PUC Economics Important Questions and Answers 2021-2022

2nd PUC Economics Important Questions with Answers Part A Micro Economics

• Chapter 1 Introduction to Micro Economics Important Questions
• Chapter 2 Theory of Consumer Behaviour Important Questions
• Chapter 3 Production and Cost Important Questions
• Chapter 4 The Theory of the Firm and Perfect Competition Important Questions
• Chapter 5 Market Equilibrium Important Questions
• Chapter 6 Imperfect Competitive Markets (Non-Competitive Markets) Important Questions

2nd PUC Economics Important Questions with Answers Part B Macro Economics

• Chapter 1 Introduction to Macro Economics Important Questions
• Chapter 2 National Income Accounting Important Questions
• Chapter 3 Money and Banking Important Questions
• Chapter 4 Consumption and Investment Function Important Questions
• Chapter 5 Government Budget and the Economy Important Questions
• Chapter 6 Open Economy Macroeconomics Important Questions

Karnataka 2nd PUC Biology Important Questions Chapter 16 Environmental Issues

Question 1.
Define pollution?
Answer:
Pollution is defined as an undesirable change in physical, chemical or biological characteristics of air, water, land, soil.

Question 2.
Name the main source of air pollution?
Answer:
Pollutants emitted by automobiles are the main sources of air pollution.

Question 3.
Name any two metals found in catalytic converter?
Answer:
Platinum and palladium.

Question 4.
In which year was Air prevention and control of pollution act amended to include noise as air pollution?
Answer:
1987.

Question 5.
Name the city in which entire public road transport runs on CNG?
Answer:
Delhi.

Question 6.
How do automobiles fitted with catalytic converters reduce air pollution? Suggest thehydro best fuel for such vehicles?
Answer:
Catalytic converters have expensive metals like platinum-palladium and rhodium as catalysts. As exhaust emission passes through catalytic converter, unbumt hydrocarbons are converted into CO₂ and H₂O, CO and NO are changed to CO₂ and N₂ gas. Unleaded petrol is the best fuel.

Question 7.
Why is CNG considered better than diesel? Explain.
Answer:

1. CNG bums more efficiently unlike diesel or petrol.
2. Very little of it is left unburnt.
3. It cannot be adulterated.
4. It is cheaper than petrol or diesel.

Question 8.
Explain any three measures which will control vehicular air pollution in Indian cities?
Answer:
Three measures used to control vehicular air pollution in Indian cities are:

1. Use of CNG as fuel in automobiles because it bums more efficiently and little of it is left unbumt. It is also cheaper.
2. Use of unleaded petrol.
3. Use of catalytic converter in the vehicles as it reduces emission of poisonous gases.

Question 9.
What is noise pollution?
Answer:
It is an undesirable high level of sound.

Question 10.
A noise of which decibel damages ear drums thus causing permanent hearing ability?
Answer:
A noise above 150 d B damages ear drums and causes permanent hearing ability.

Question 11.
Define water pollution?
Answer:
Water pollution is any undesirable change in the physical, chemical, biological properties of water.

Question 12.
Define Bio-magnification?
Answer:
An increased concentration of toxins at successive trophic levels is termed as Bio-magnification.

Question 13.
What is Eutrophication?
Answer:
It is natural aging of a iake by biological enrichment of its water.

Question 14.
Define B O D (Biochemical oxygen demand)?
Answer:
The amount of oxygen required for microbial breakdown of biodegradable organic matter is called biochemical oxygen demand.

Question 15.
What are algal blooms?
Answer:
Domestic sewage contains nutrients like nitrogen and phosphorous which favour the excessive growth of planktonic algae termed as algal blooms.

Question 16.
What are the various constituents of domestic sewage? Discuss the effects of sewage discharge on a river?
Answer:
Various constituents of domestic sewage are:

• Suspended solids – Grit made of sand, silt and clay.
• Colloidal material – Includes faecal matter, bacteria, paper fibers.
• Dissolved solids – They are inorganic nutrients and organic compounds
• Pathogens – A number of pathogens cause various diseases like typhoid, cholera, dysentery etc

Effects of sewage discharge on a river:
Domestic sewage mainly contains biodegradable organic wastes which are decomposed by decomposers like bacteria and other microorganisms. Decomposers require O₂ for their activity and hence BOD increases. Many aquatic organisms die due to a lack of dissolved O₂. Domestic sewage contains N₂ and P which favours excess growth of algae called algal bloom. Excessive growth of water hyacinth imbalances the water ecosystem and thus the aquatic animals die.

Question 17.
What is the raw material for poly blend?
Answer:
Plastic wastes.

Question 18.
Expand F O A M?
Answer:
Friend of Areata Marsh.

Question 19.
Where were Ecosan toilets first developed?
Answer:
Kerala, Sri-Lanka.

Question 20.
How solid wastes are categorized and disposed?
Answer:
Solid Wastes:
Discarded solid materials produced due to various human activities. They are of following types

1. Municipal solid wastes- wastes from homes, offices, schools, hospitals that are collected and disposed of by the municipality which generally consists of paper, leather, textile, rubber, glass, etc
2. Industrial wastes – it includes scraps, fly ash etc
3. Hospital wastes include hazardous waste containing disinfectants and other harmful chemicals generated by hospitals.
4. E wastes(electronic wastes)- Damaged electronic goods and irreparable computers.

Methods of Solid Waste Disposal:

1. Open burning.
2. Sanitary landfills
3. Ragpickers
4. Natural breakdown
5. Recycling
6. Incineration

Remedy for plastic waste: A fine powder of recycling modified plastic is called poly blend. It is miked with bitumen to lay roads in Bangalore.

Question 21.
Mention how e wastes is produced and disposed off. Write the solution for its treatmen?
Answer:
Irreparable computers and other electronic goods are termed as e wastes. They are buried in landfills or incinerated. Recycling is the only treatment for e wastes.

Question 22.
What is polyblend?
Answer:
A fine powder of recycling modified plastic is called polyblend.

Question 23.
What is the cause of Radioactive pollution?
Answer:

1. Leakage of radioactive materials from power plants
2. Unsafe disposal of radioactive wastes.

Greenhouse effect and Global Warming:
The progressive warming of the earth’s surface due to an increase of greenhouse gases is called greenhouse effect.
Green house gases – CO₂, CH₄(methane), N₂O(Nitrous oxide) CFC, and water vapour.

Significance of greenhouse effects:

• It is essential to make the earth warmer for organisms to live otherwise the earth will have frozen temperature around -18C.
• Global warming: It is the heating up of earth due to green house effect or increase in mean temperature of earth due to greenhouse gases is called global warming.
• The term green house has been derived from a phenomenon that occurs in green house.

Question 24.
Discuss the consequences of (a) Global warming (b) Ozone depletion.
Answer:
Global warning: It is the heating up of earth due to greenhouse effect or increase in mean temperature of earth due to greenhouse gases is called global warming. –

Effects:

1. The temperature of the earth has increased by 0.6° C in the last three decades and it leads to changes in precipitation patterns
2. The rise in temperature leads to deleterious changes in the environment resulting in odd climatic changes called the EL Nino effect.
3. The rise in temperature will lead to increased melting of polar ice caps which will cause the rise in sea level.

Causes of Ozone depletion:
(a) O₃ degradation has increased due to chloroform carbons (CFCs)
(b) CFCs are refrigerants that react with UV in stratosphere to release chloride atoms.
(c) Chloride atoms act as catalysts to degrade ozone and release molecular oxygen.
(d) CFCs have permanent and continued effect as chlorine atoms are not consumed.
(e) Over the Antarctic region there has been thinning of large area of ozone layer which has resulted in the formation of ozone holes.

Question 25.
Name any three gases contributing to greenhouse effect?
Answer:
CO₂, Nitrous oxide, CH₄

Question 26.
Name two greenhouse gases produced by anaerobic microbes?
Answer:
CO₂, and CH.

Question 27.
What type of UV radiation can be lethal to organisms?
Answer:
UV-B radiation.

Question 28.
Write the unit used for measuring ozone thickness?
Answer:
Dobson Units

Question 29.
How is snow blindness caused in humans?
Answer:
In human eye, cornea absorbs UV-B radiation and a high dose of UV-B causes inflammation of the cornea causing snow blindness.

Question 30.
Which of the following is not a green house gas? CO₂, CH₄, O₂, CFCs?
Answer:
O₂

Question 31.
What is global warming? List four strategies for reducing global warming?
Answer:
Increase in the level of green house gases in the atmosphere causes the rise in global mean temperature called global warming.

Four strategies for reducing global wartning are:

1. Reducing deforestation
2. Planting trees
3. Slowing down the growth of human population
4. Reduction in emission of greenhouse gases.

Question 32.
Chlorofluorocarbons CFCs are widely used as refrigerants. Then why it is suggested to reduce its emission as far as possible? Explain.
Answer:
CFCs are widely used as refrigerants. CFCs discharged in the lower part of atmosphere move upward and reach the stratosphere. In stratosphere UV rays act on them releasing chloride atoms. Chloride atoms degrade O₃ releasing molecular O₂. Whatever CFCs are added to the stratosphere have permanent and continuing effects on O₃.

Question 33.
Write short notes on:
Answer:
(a) Greenhouse gases
(b) O₃ depletion.

(a) Greenhouse gases – CO₂, CH₄(methane), N₂O(Nitrous oxide) CFC and water vapour.
Significance of greenhouse effects:
It is essential to make the earth warmer for organisms to live otherwise earth will have frozen temperatures around -18C.

(b) Causes of Ozone depletion:
(a) O₃ degradation has increased due to chloroflouro carbons (CFCs)
(b) CFCs are refrigerants which react with UV in stratosphere to release chloride atoms.
(c) Chloride atoms act as catalysts to degrade ozone and release molecular oxygen.
(d) CFCs have permanent and continued effect as chloride atoms are not consumed.
(e) Over the Antarctic region there has been thinning of large area of ozone layer which has resulted in the formation of ozone holes.

1. Deforestation is defined as conversion of forested area to non-forested area.
2. Removal of forest areas to fulfill the need of growing human population is called deforestation.
3. Almost 40% forests have been lost in the tropics and 1% in the temperate region.

Causes of deforestation:
(a) Human settlements.
(b) Forest fires
(c) Hydroelectric projects
(d) Overgrazing by livestock.
(e) Demand for wood.
(f) Jhum cultivation or slash and bum agriculture – The farmers cut the forest trees and bum the plant remains. The land is then used for farming and cattle grazing. After cultivation, the land is left barren for years.

Effects of deforestation:

1. Increase in CO₂ concentration in the atmosphere.
2. Loss of biodiversity due to habitat destruction.
3. Disturbance in hydrologic cycle.
4. Soil erosion that may lead to desertification.

Reforestation:
It is a process of restoring a forest that once existed but was removed at some point of time in the past. It may occur naturally in a deforested area.

People’s Participation in Conservation of Forests:

1. In 1731, a Bishnoi woman Amrita Devi, showed exemplary courage by hugging a tree in order to prevent its cutting. Her three daughters and hundreds of other Bishnoi’s followed her and were killed by soldiers of king of Jodhpur.
2. The Government of India has instituted Amrita Devi Bishnoi Wild life protection award for individuals or communities from rural areas that shows extraordinary courage and dedication in protecting wildlife.
3. Chipko movement was started in Garhwal Himalayas in 1974 by Sri Sundarlal Bahuguna to prevent cutting down of trees. Local women hugged trees to prevent their cutting.
4. In 1980, the Government of India has introduced the concept of Joint Forest Management to work closely with the local communities for protecting and managing forests on mutual benefits.

→ Pollution is defined as an undesirable change in physical, chemical or biological characteristics of air, water, land or soil.

Pollutants are the agents which bring about an undesirable change in the properties of air, water and soil.
Govt, of India has passed the Environment Protection Act 19861 protect and improve the quality of environment.

→ Air Pollution:
Any undesirable change in the physical, chemical or biological characteristics of air that exerts adverse effects on human beings is defined as air pollution.

→ Causes:
(a) Smoke from forest fires, volcanic eruptions etc
(b) Decomposition of garbage resulting in release of unwanted gases into the atmosphere.
(c) Burning of fossil fuels in automobiles and industries release particulate and air pollutants
(d) Use of leaded petrol.
(e) Gaseous wastes or particulate byproducts of various industries.

(ii) Air pollutants can be classified into two groups.
(a) Particulate pollutants eg metallic particles, dust particles, soot and smoke.
(b) Gaseous pollutants eg. CO, NO₂, nitrogen hydrogen sulphide H₂S, Sulphur dioxide SO₂ etc.

→ Harmful Effects:
(a) Carbon Monoxide causes giddiness, headache, decreased vision, cardiovascular malfunction, asphyxia.
(b) H₂S causes nauses, eye and throat irritation.
(c) Sulphur dioxide causes respiratory tract diseases like asthma, bronchitis, cancer, emphysema etc.
(d) Fine particulates cause breathing, respiratory symptoms, irritation, inflammations and damage of the lungs.

→ Control Methods Of Air Pollution
(a) Electrostatic precipitator(ESP).

• It is an electrical device to remove particulate matter present in the exhaust of thermal power plant.
• More than 99% of particulate matter can be removed by this method.
• ESP has electrode wires’and a stage of collecting plates.
• Electrode wires are provided with electric current of several thousand volts which produces a corona that releases electrons.
• These electrons attach to dust particles and give them a negative charge with in a small fraction of second.
• Collecting pates are earthed so that they can attract dust particles.

(b) Scrubber

• It is used to remove gases like sulphur dioxide from industrial exhaust.
• The exhaust is passed through a spray of water or lime.
• Water dissolves gases and lime reacts with S02 to form a precipitate of calcium sulphate and sulphide. Clean air

(c) Catalytic converters

• They are fitted into automobiles for reducing the emission of poisonous gases like NO₂ and CO.
• They have expensive metals like platinum-palladium and rhodium as catalysts.
• Motor vehicles fitted with catalytic converter should use unleaded petrol as leaded petrol inactivates the catalyst.

→ Control Of Air Pollution In Delhi:

1. All buses of Delhi were converted to run on CNG by end of 2002.
2. Advantages of CNG over diesel/petrol.
   (a) CNG bums more efficiently without leaving any unbumt remnant behind.
   (b) CNG is cheaper than petrol or diesel.
   (c) CNG cannot be siphoned by thieves and adulterated like petrol or diesel.

→ Noise Pollution:
Noise is defined as undesired high level of sound.
Causes

1. Loudspeakers and music systems used for entertainment.
2. Jet planes and rockets.
3. Industrial noises.

→ Harmful Effects:

1. Sleeplessness
2. Stress
3. Increased rate of heartbeats
4. Breathing problems.
5. Damage of eardrums impairing hearing ability permanently.

→ Control Methods:

1. Industrial noises can be reduced by using sound absorbent materials or by muffling noise.
2. Delimitation of the home-free zone around hospitals and schools.
3. Stringent laws should be laid for permissible sound levels of crackers and loudspeakers.
4. Setting timing after which loudspeakers cannot be played.

→ Water Pollution:
Water pollution is an undesirable change in the physical, chemical, biological properties of water that may affect human beings and domestic species.

Water pollution is caused due to:
1. Domestic Sewage

• Domestic sewage contains
• Suspended solids. Ex. Sand, Silt, Clay
• Colloidal materials ex. Faecal matter, bacteria, paper, cloth etc
• dissolved materials ex. Nitrates, sodium, calcium salt.
• Domestic sewage has biodegradable organic wastes which can be decomposed by decomposers.

2. Industrial Wastes

• Industries like petroleum, paper manufacturer release waste water containing heavy metals like mercury and many organic compounds
• Mercury, DDT are well known for Biomagnification.
• Bio-magnification is increased concentration of toxins at successive trophic levels. Toxic substances cannot be metabolized or excreted and therefore get accumulated in an organism and are passed onto higher trophic levels.

3. Eutrophication – It is natural aging of a lake by biological enrichment of its water. Water in a young lake is
cold and clear and with time it gets enriched with nutrients which encourages growth of aquatic plant life and animal life.

4. BOD (biochemical Oxygen Demand) – The amount of 02 required for microbial breakdown of biodegradable organic matter is called BOD. It is higher in polluted water and less in drinking water. (March 2014 and 2015)

5. Algal bloom – (March 2014) Domestic sewage contains nutrients like nitrogen and phosphorus which favour the excessive growth of planktonic (free-floating) algae called an algal bloom. Algal bloom causes fish mortality and deterioration of water quality.

6. Heated thermal waste waters flowing out of electricity generating unit. Ex: Thermal power plants constitute another important category of pollutants. Thermal wastewater eliminates or reduces the number of organisms sensitive to high temperature and may enhance the growth of plants and fish only after causing damage to flora and fauna.

→ Integrated Waste Water Treatment:
Wastewater including sewage can be treated by using a mix of artificial and natural processes.
Cleaning includes:

1. Conventional sedimentation, filtering, chlorine treatment.
2. Biologists developed six connected marshes over 60 hectares of marshland which included algae, fungi, bacteria. FOAM (Friends of Areata Marsh)are safeguarding this project.
   Ecosan toilets has been developed in Kerala, Sri-Lanka for ecological sanitation.

→ Solid Wastes:
Discarded solid materials produced due to various human activities. They are of following types

1. Municipal solid wastes- wastes from homes, offices, schools, hospitals that are collected and disposed by municipality which generally consists of paper, leather, textile, rubber, glass etc
2. Industrial wastes – it includes scraps, fly ash etc
3. Hospital wastes include hazardous waste containing disinfectant and other harmful chemical generated by hospitals.
4. E wastes(electronic wastes)- Damaged electronic goods and irreparable computers.

→ Methods of Solid Waste Disposal:

1. Open burning.
2. Sanitary landfills
3. Ragpickers
4. Natural breakdown
5. Recycling
6. Incineration

Remedy for plastic waste: A fine powder of recycling modified plastic is called poly blend. It is mixed with bitumen to lay roads in Bangalore.

→ Soil Pollution:
Undesirable changes in soil profile affecting its productivity are called soil pollution.

Causes:

1. Chemical seepage from industries.
2. Inorganic fertilizers and pesticides.

→ Harmful Effects:

1. Non-target organisms in the soil are killed.
2. Soil becomes infertile.
3. Pesticides can results in bio-magnification.

→ Control Methods:

1. Safe disposal of industrial wastes.
2. Organic farming- it is a zero-waste procedure where waste products from one process are cycled in as nutrients for other processes allowing maximum utilization of resource and increasing the efficiency of production.

→ Case Study of Organic Farming:

• Ramesh Chandra Dagar includes beekeeping, dairy management, water harvesting, composting and agriculture in a chain of processes.
• Chemical fertilizers are not required as cattle excreta is used as manure.
• Crop wastes is used for making compost which is used as a natural fertilizer. Compost generates natural gas which is used for energy needs on farm.

→ Radio – Active Pollution:
Nuclear energy was assumed to be a natural non-polluting way of electricity generations till the incidents at three mile Island and Chernobyl. It is now considered as the most potent pollutant.
Causes:

1. Leakage of radioactive materials from power plants.
2. Unsafe disposal of radioactive wastes.

→ Harmful Effects:

1. Radiations from nuclear waste causes mutation at a very high rate.
2. At high doses, nuclear radiations are lethal.
3. At low doses, radiation causes disorders and cancer.

→ Effects

1. The temperature of the earth has increased by 0.6″ C in the last three decades and it leads to changes in precipitation patterns
2. Rise in temperature leads to deleterious changes in environment resulting in odd climatic changes called the EL Nino effect.
3. Rise in temperature will leads to it increased melting of polar ice caps which will cause the rise in sea level.

→ Control of Global Warming:
Global warming can be controlled by:
(a) Reducing deforestation
(b) Planting trees (afforestation).
(c) Slowing down the growth of human population.
(d) Reduction of emission of green house gases into the atmosphere.
(e) Cutting down use of fossil fuels
(f) Improving efficiency of energy usage.

→ Ozone Depletion:
Ozone is of two types-

1. Bad ozone formed in troposphere and is harmful to plants and animals.
2. Good ozone formed in the stratosphere and absorbs harmful UV radiations from the sun. Thickness of ozone is measured in Dobson units (D U).

→ Formation of Ozone:
Nascent oxygen combines with molecular (O₂) to form ozone by the action of UV rays (Equation)
Ozone is degraded into molecular oxygen in the stratosphere by the UV action to maintain a balance between production and degradation.

→ Causes of Ozone Depletion
(a) O₃ degradation has increased due to chloroflouro carbons (CFCs).
(b) CFCs are refrigerants which react with UV in stratosphere to release chloride atoms.
(c) Chloride atoms act as catalysts to degrade ozone and release molecular oxygen.
(d) CFCs have permanent and continued effect as chloride atoms are not consumed.
(e) Over the Antarctic region there has been thinning of large areas of ozone layer which has resulted in the formation of ozone holes.

→ Harmful Effects:
(a) UV -B damages DNA and proteins of living organisms causing mutation.
(b) It causes skin aging, skin cell damage and skin cancers.
(c) UV-B is absorbed by human eye and at high dose it causes inflammation of cornea. This is called as snow blindness cataract.

→ Control of Ozone Depletion:
(a) An international treaty, Montreal Protocol, was signed at Montreal Canada in 1987 to curb the emission of ozone-depleting substances.
(b) More protocol has been laid down in controlling emission of CFCs.

2nd PUC Biology Important Questions with Answers

Karnataka 2nd PUC Biology Important Questions Chapter 15 Biodiversity and Conservation

Question 1.
Define biodiversity?
Answer:
The combined diversity at all the levels of biological organization is biodiversity.
Or
The sum total of all kinds of life forms of the biosphere.

Question 2.
Define biodiversity? Write any two types of biodiversity.
Answer:
The combined diversity at all the levels of biological organization.
Two types:

1. Genetic diversity
2. Species diversity.

Question 3.
Name the scientist who popularized the term biodiversity.
Answer:
Edward Wilson.

Question 4.
Mention three levels of biodiversity.
Answer:
Genetic diversity, Species diversity and Ecological diversity.

Question 5.
Explain genetic diversity with examples.
Answer:
A single species showing high diversity at the genetic level over its distributional range.
Example:

1. Rawolfia vomitoria a medicinal plant growing in different regions of Himalayan ranges shows differences in potency and concentration of an active chemical called reserpine due to genetic diversity. .
2. India has more than 50000 genetically different strains of rice 1000 varieties of mango.

Question 6.
What is species diversity? Give an example.
Answer:
The diversity at the species level in a given area. Eg: The western Ghats have greater amphibian species diversity than the eastern diversity.

Question 7.
What is ecological diversity.? Give one examlpaes.
Answer:
Diversity at ecosystem or at habitat level. Eg: India has one of the richest diversity of habitats like deserts; rain forests, mangroves, coral, etc than Norway.

Question 8.
Write a note on the latitudinal gradient pattern of animal and plants distribution.
Answer:
The latitudinal gradient is an index used to show the distribution of fauna and flora from the poles to the tropic. In general species diversity decreases as we move away from the equator towards the poles.

Eg: Tropics harbor more species than temperate or polar areas.
Colombia – 1400 species of birds, India has 1200 species New York has 105 species and green land has 56 species.
The tropical Amazon forest has the greatest biodiversity on earth. It is home to more than 40000 species of plants, 3000 fishes, 1300 birds, 427 mammals, 378 reptiles, and 125000 invertebrates.

Question 9.
Why tropics account for their greater biological diversity.
Answer:

1. Tropical latitudes have remained relatively undisturbed for millions of years and thus had a long evolutionary time for species diversification.
2. Tropical environments are bees seasonal relatively more constant and predictable, which leads to niche specialization and lead to a greater species diversity.
3. There is more solar energy available in the tropics which contributes to higher productivity.

Question 10.
Describe species – Are a relationships to explain fundamental ecological relationships.
Answer:

• Alexander von Humboldt observed that “Speties richness increases with increase explored area but up to a certain limit” As the area of the region increases the number of species.
• The relation between species richness and area for a wide variety of taxa turns out to be a rectangular hyperbola.
• On a logarithmic scale, the relationship is a straight line described by the equation.

Log S = Log C + Z log A
Where S = Species richness, A = Area
Z = Slope of the line, & C = Y intercept.
Ecologists have discovered that value of Z line in the range 0.01 to 0.02 regardless of taxonomic group or the region.
We will find the slope of the line much steeper in species are relationships among very large areas like the entire continents.

Question 11.
List the characters of a stable community in an ecosystem.
Answer:
Communities with more species tend to be more stable than those with fewer species. Community should not show too much variation in productivity from year to year. And it must be resistant to occasional disturbances and invasion of alien species.

Question 12.
Write a note on David Tilman’s long-term ecosystem experiments?
Answer:
He found that plots with more species showed less year to year variation in total biomass.and he also showed that increased diversity contributed to higher productivity from his experiments.

Question 13.
Explain the rivet popper hypothesis?
Answer:

1. Paul Ehrlich put for ward rivet popper hypothesis to explain the importance of each species.
2. He compared each species to rivets in an airplane, and airplane to ecosystem If these rivets are removed by passengers traveling in it, to take home (i.e, species extinct popping) it may not affect the flight safety initially but if more rivets are removed the plane becomes dangerously weak, and if continued it may become critical.
3. Hypothesis says that ecosystem is important, and when disturbed, it results in decreasing the ecological balance.
4. Loss of rivets on the wings of airplane (key species that drive major ecosystem functions) is obviously a more serious threat to flight safety, than loss of a few rivets on the seats or windows inside the plane.

Question 14.
Mention the number of extinct species as listed under IUCN red list (2004).
Answer:
IUCN documents 784 spegies which includes 338 vertebrates, 359 invertebrates and 87 plants.

Question 15.
Name any four recent extinct organisms as per IUCN Red List.
Answer:
Dodo, Quagga, Thylarine, Steller’s sea cow and three subspecies of tiger namely Bali, Javan and Caspian .

Question 16.
Which group of animal kingdom appears to be more vulnerable to extinction.
Answer:
Amphibians.
[Note: Since the origin and diversification of life on earth there were five episodes of mars extinction of species. Presently the sixth mars extinctions is in progress, where we can see different in rates the current rates are 100 to 1000 times farter than in pre human times. Our activities are responsible for the faster extinction rates, if continues like this, all the species on earth might be wiped out within the next 100 years].

Question 17.
Explain the effects of loss of biodiversity in a region.
Answer:
Decline in plant production. Lowered resistance to environmental conditions like drought.
Increased variability in certain ecosystem processes such as plant productivity, water use, and pest and disease cycles.

Question 18.
Mention ‘The Evil Quartet’ of biodiversity loss.
Answer:

1. Habitat loss and fragmentation.
2. Alien species invasions.
3. Co-extinctions.
4. Overexploitation.

Question 19.
List out any two effects of loss of biodiversity.
Answer:

1. Co-extinctions.
2. Overexploitation.

Question 20.
Introduction of some alien species cause s biodiversity loss, Justify the statement With an example.
OR
Alien species invasion leads to extinction of indigenous species justify the statement by considering two animals as examples purposes in posing a threat to the indigenous.
Answer:
Alien species are the species which are translocated beyond its home range. This intentional or chance introduction of exotic species into new territories by humans adversely affects the native species.
Examples:

1. Introduction of Nile perch into Lake Victoria, led to extinction of more than 200 species of Cichlid fish in the lake.
2. African catfish Glarions gariepinces for aquaculture, Catfishes in our rivers.

Question 21.
Explain 3 causes of biodiversity losses with examples.
Answer:
1. Habitat loss and fragmentation: The destruction of ecosystem by human, activities is the most important
cause for driving animals and plants to extinction.
Due to fragmentation of habitats by humans mammals and birds requiring large territories and certain animals with migratory habit are badly affected leading to population declines.
Eg: Tropical rainforests – These once covered more than 14% of earth’s land surface are now not more than 6%. The amazon rain forest millions of species is being cut and cleared for cultivation soya beans or conversion to grasslands for raising beef cattle.

2. Over-exploitation: Humans have always depended on nature for food and shelter, harvesting these sources to the point of extinction or diminishing leads to overexploitation.
Ex: Steller’s sea Low and passenger pigeon were extinct due to overexploitation by humans. Overfishing of much marine fish populations around the world endangering their existence.

3. Co-extinctions: The simultaneous extinction of two or more species. When one species become extinct, the plant and animal species with it also becomes extinct.
Eg: 1. If host fish becomes extinct, parasites that depend on it also become extinct.
2. Mutualism of plant – pollinators, where extinction of one leads to the extinction of the other.

Question 22.
How does fragmentation of large habitats due to human activities lead to population decline?
Answer:
Increased risk of genetic consequences, climatic changes and less adaptability leads to population decline.

Question 23.
Explain benefits commonly listed for the biodiversity conservation.
Answer:
There are many reason for conservation. They can be grouped into three sections.
1. Narrowly utilitarian: It focuses the essential services rendered by biodiversity with respect to economic benefits from nature which includes food, firewood, fibre construction material, industrial products and products of medicinal importance.

2. Broadly utilitarian: This arguments says that biodiversity plays a major role in many ecosystem services that nature provides.

• Amazon forest is estimated to produce 20% of total oxygen in the earth’s atmosphere.
• Pollination is another service ecosystems provide through pollinators.
• Aesthetic values.

3. Ethical: Ethical aspect puts forth certain moral principles or rules to conserve biodiversity. We need to realize that every species has an intrinsic value even if it is not of economic value

Question 24.
Define Bioprospecting.
Answer:
Bioprospecting is a process used for exploring molecular, genetic and species-level diversity for products of economic importance in the medicinal field.

Question 25.
Mention the two types of biodiversity conservation?
Answer:
In-situ conservation & Ex-situ conservation.

Question 26.
What is Ex-Situ conservation? Mention two examples.
Answer:
In this approach the conservation of species outside their natural habitats.
Eg: Botanical gardens, Zoo gene bank, seed bank, cryopreservation, tissue culture.

Question 27.
What is In-Situ conservation? Mention two examples?
Answer:
In this approach the conservation of species in their natural habitats or on site conservation.
Ex: Biosphere, reserves, National park, Sanctuaries.

Question 28.
What are biodiversity hot spots.
Answer:
These are the regions with very high levels of species richness high degree of endemism and with accelerated habitat loss.

Question 29.
Name the hot spots of India.
Answer:
The Western Ghats, and Sri Lanka, Indo-Burma and Himalaya and North Eastern Himalayas.

Question 30.
How many hot spots are there in the world?
Answer:
34 Hot spots.

Question 31.
What are sacred groves? Mention any two examples.
Answer:
Sacred grooves are the traditionally conserved patches of forest where dedicated to local deities considering the landscape as sacred. Eg: Aravalli Hills in Rajasthan, the Western Ghats in Karnataka and Maharashtra, Khasi hills of Meghalaya. Sarguja, Chanda, and Bastar areas of Madhya Pradesh.

Question 32.
What is endemism?
Answer:
Species are confined to a particular geographical region and not found anywhere.

Question 33.
Mention the number of Biosphere reserves, National parks, and Wild Life Sanctuaries in India.
Answer:
Biosphere reserves – 14, National Parks – 90 Wild Life Sanctuaries – 448.

Question 34.
Write a note on international efforts for conserving Biodiversity.
Answer:
Biodiversity conservation is a important global issue. The historic convention on biological diversity was ‘The Earth Summit’ held in Rio de Janeiro (1992) which called all nations to conserve biodiversity:
The World summit on sustainable development held in 2002 in Johannesburg, South Africa, where 190 countries pledged their commitment to achieve by 2010 a significant reduce in Biodiversity loss.

→ Biodiversity:
The rich variety of living organisms with which they share this planet are always astonishing and fascinating to humans. It is hard to believe that there are more than 20000 species of ants, 300000 species of beetles, 28000 species of fishes and nearly 20000 species of orchids

→ How Many Species are There On Earth and How Many in India
The total number of plant and animal species is more than 1.5 million as listed by IUCN (2004).
According to Robert may global species diversity is 7 million.
Animal species 70% and plants 22% of the total.

Among animals insects share 70% of the total with most species richness.
India having only 2.4% of worlds land area shares 8.1 percent of the global species diversity and considered One of the 12 mega diversity countries of the world.

→ Why Should We Conserve Bio-Diversity
We need to conserve biodiversity in order to maintain our own life, which demands planned management programmer.

2nd PUC Biology Important Questions with Answers

Karnataka 2nd PUC Biology Important Questions Chapter 14 Ecosystem

Question 1.
Define Ecosystem?
Answer:
Ecosystem: It is a functional unit of nature. “It is an interaction between living organisms, among themselves and also with the surrounding physical environment”.

Question 2.
Give any two examples of Terrestrial and Aquatic man made ecosystem?
Answer:

1. Terrestrial ecosystem: Ex: Forest, grassland and desert.
2. Aquatic ecosystem: Ex: Pond, lake, wetland, river and estuary.
3. Man made ecosystem Ex: Crop field, Aquarium.

Question 3.
Mention the structural component of ecosystem?
Answer:
Interaction of abiotic and biotic component result in a physical structure and that is characteristic for each type of ecosystem.

Question 4.
What is species composition of an ecosystem?
Answer:
Species Composition is an “Identification and description of plant and animal species of an ecosystem”.

Question 5.
Define stratification? Give an example.
Answer:
Stratification is a “Vertical description of different species occupying different levels in an ecosystem.

Ex: Tree occupy top layer of forest, shrubs secpnd and herbs and grasses bottom layers.

Question 6.
Give an example of an ecosystem to understand distribution and role of components?
Answer:
To understand distribution and role of components in a ecosystem, Pond is considered as ain example.

Question 7.
Describe pond ecosystem along with basic events?
Answer:
Abiotic Components:

• Water with all the dissolved inorganic and organic substances.
• Rich soil deposits at the bottom of the pond.
• Solar input, temperature, day length and climatic conditions.

Biotic Components:
Autotrophes: Phytoplankton’s, Algae, Floating, (producers) submerged and marginal plants at the edge of pond. Consumers: Zooplankton, swimming and bottom dwelling animals.
Decomposers: Fungi, bacteria and flagellates at the bottom of the pond.

Above systems performs all the functions of an Ecosystem.

• Producers convert inorganic into organic materials with the help of radiant energy of the sun.
• These autotrophs are consumers by heterotrophs (consumers).
• Decomposers decompose and release them back which is reused by autotrophs.
  Thus there is a cyclic exchange of materials between living and abiotic environment in pond ecosystem.

Question 8.
Name functional compositions of ecosystem?
Answer:
The components of the ecosystem are seen to function as a unit.

1. Productivity
2. Decomposition
3. Nutrient recycling.

Question 9.
Define productivity?
Answer:
‘Productivity is the rate of synthesis of biomass produce at any trophic level during a given period of tune” It is measured as weight (g/m²) or energy (k/cal/m²).

Question 10.
Differentiate between primary and secondary productivity?
Answer:

Primary productivity	Secondary productivity
It is the rate of production of biomass or organic matter per unit area by producers	It is the rate of productivity of biomass or organic matter per unit area by consumers.

Primary productivity is further classified into 2 types.

Question 11.
Differentiate between GPP and NPP?
Answer:

(GPP) Gross primary productivity	(NPP) Net primary productivity
It is the total amount of food/organic matter or biomass produced by the producers during photosynthesis.	It is the small amount of GPP by plants in Respiration (R) NPP = GPP – R

[Note:

1. The annual NPP of the biosphere is 170 billion tons of organic matter.
2. Ocean contribute only 55 billion tons and the remaining 115tons is by land.]

Question 12.
Define decomposition and represent decomposition cycle in terrestrial ecosystem?
Answer:
“The process of breaking down of complex organic matter into inorganic substances like Carbon dioxide, Water and Nutrients in nature”is known as decomposition.

Question 13.
Define detritus? or Detritivores.
Answer:
Dead plant remains such as leaves, bark, flowers, fruits, and dead remains of animals including faecal matter constitute detritus or detritus feeding invertebrates are known as detritivores.

Question 14.
Why Earth worms are known as farmer’s friend?
Answer:
They break down the complex organic matter and help in loosening the soil for aeration and helps in growth of plants. They are known as detrivores.

Question 15.
Explain the steps involved in Decomposition?
Answer:
Important steps in the process of Decomposition:

1. Fragmentation: Breaking down detritus into smaller particles by detrivores.
2. Leaching: Water-soluble inorganic nutrients produced during decomposition, go down into deeper layers of soil and get precipitated as unavailable salts
3. Catabolism: Bacterial and Fungal enzymes degrade detritus into simpler inorganic substances.
4. Humification: The simplified detritus gets converted into dark coloured amorphous substances called humus in the soil. This process is Humification. It serves as reservoir of nutrients.
5. Mineralisation: The humus further is degraded by microbes and inorganic nutrients are released into the soil. It is the formation of minerals.

Question 16.
Mention the factors which regulate decomposition?
Answer:
Factors which regulate Decomposition:

• Oxygen is required.
• Chemical composition of detritus and climatic factors
• Slow in detritus containing lignin and chitin.
• Faster in detritus with Nitrogen and water soluble sugars. . .
• Warm and moist environment favour decomposition.

Question 17.
Write a note on energy flow or Given an account of energy flow in an Ecosystem?
Answer:

1. Sun is the only source of energy for all Ecosystems on earth.
2. Less than 50% of incident solar radiation is Photosynthetically Active Radiation (PAR). Photosynthetically active radiation. It is unidirectional, which flows from producers to herbivores to carnivores.
3. Producers capture only 2-10% of solar radiation, some is lost as heat, where some energy is used in respiration of producers and also providing food for herbivores and then to decomposers. So only 10% of herbivore productivity is used to support carnivore productivity and much least energy will reach the top carnivore.

Question 18.
Define PAR?
Answer:
PAR is the amount of light (400-700nm) available for photosynthesis. (Light wave length range).

Question 19.
What is ten percent law?
Answer:
Plants capture only 2-10 percent of the photosynthetically active radiation, there is unidirectional flow of energy through food chain.

Question 20.
What are producers? Give examples.
Answer:
Producers: “Green plants”. These are the photosynthetic organisms which are capable of synthesizing their own food using sunlight. Primary consumers depend on these producers. Ex: phytoplanktons, Algae and higher plants.

Question 21.
What are consumers?
Answer:
Consumers: Organisms which depends on other plants or organisms for their food needs. Also known as heterotrophes.

Question 22.
Mention the consumer types with an example?
Answer:

1. Primary consumers (Herbivores) feed on producers
2. Secondary Consumers (Primary carnivores) feeds on herbivores
3. Tertiary consumers (Secondary carnivores) feed on secondary consumers.

Question 23.
Define food chain?
Answer:
Food chain describes the structure and function of the various trophic levels and function of the various trophic levels and their interrelationship in an Ecosystem. [A series of organisms each dependent on the next as a source of food].

Question 24.
Differentiate between Grazing Food Chain (GFC) and Detritus Food Chain (DFC)?
Answer:

Question 25.
Which is the major channel for energy flow in aquatic ecosystem?
Answer:
Grazing Food Chain – is major channel for energy flow in aquatic Ecosystem.

Question 26.
Which is the major channel for energy flow in terrestrial ecosystem?
Answer:
Detritus Food Chain – is major channel for energy flow in terrestrial ecosystem.

Question 27.
Define food web?
Answer:
“It is a network of food chains, which becomes interconnected at various trophic levels in an Ecosystem.

Question 28.
Define trophic level?
Answer:
Organism occupy a specific place in the food chain based on the source of their food is known as trophic level.

The amount of energy decreases from first trophic level to the last, trophic level. Representation of trophic levels in an Ecosystem.

Question 29.
Represent different trophic levels of Ecosystem with examples?
Answer:

Question 30.
Define standing crop?
Answer:
Standing crop: Each trophic level has a certain mass of living material at a particular time. It measures as biomass or the number in a unit area. [Note: Measurement of biomass in terms of dry weight is more accurate].

Question 31.
Define Ecological Pyramids and mention its types?
Answer:
It is a graphical representation of various trophic level of a food chain. Pyramid of number, Pyramid of Energy,
Pyramid of Biomas.
[Notes:

• It is expressed in terms of number, biomass and Energy.
• The base of each pyramid represents producers and the top represent the tertiary consumer.]

Question 32.
Describe the types of Ecological pyramids?
Answer:
Pyramid of numbers: It is a graphic representation of the numbers of individuals in the various trophic level of food chain.

• Pyramid of number in most Ecosystems is upright.
• In tree ecosystem it is inverted.

OR
Diagrammatically represent the pyramid of number in an Ecosystem?
OR
Represent pyramid of number in grassland ecosystem.
Answer:

OR
Define pyramid of biomass?
Answer:
“It is a graphic representation of Biomass present per unit area at different trophic levels of food chain.
OR
Give diagrammatic representation of Pyramid of Biomass?
Answer:

OR
Define pyramid of energy?
or
Define Ecological pyramid? Describe pyramid of Energy flow with example?
or
Draw an ideal pyramid of energy and mention the units?
Answer:
“It is the graphic representation of amount of energy trapped per unit time and area in different trophic levels of a food chain”.

Question 33.
Why pyramid of energy is always upright?
Answer:
Pyramid of energy is always upright, because when energy flows from a particular trophic level to the next, some energy is always lost as heat at each step. Limitations of Ecological Pyramids.

Question 34.
List the limitations of ecological pyramids?
Answer:

• A species may occupy more than one trophic level in the same ecosystem at the same time.
• It assumes a simple food chain.
• It does not accommodate a food web
• Saprophytes are not taken into account in ecological pyramids.

[Note: If producers are more in number and biomass than the consumers – Upright pyramid. Ex: Grassland (Biomass and Energy)].

If the number of producers is less than the consumers – Inverted pyramid. Ex: Aquatic Ecosystem (Bio¬mass), Tree Ecosystem (Number)].

Question 35.
What is ecological succession?
Answer:
Ecological succession: “The gradual and fairly predictable change in the species composition of a given area”.

Question 36.
With reference to ecological succession define the following:
(a) Climax community
(b) Sere
(c) Pioneer species
Answer:
Climax community: The composition and structural changes lead finally to a community that is near equilibrium with the environment, or Final community that established and maintain equilibrium with physical environment.

Sere: The entire sequence of communities that successively change in a given area.

Pioneer Species: The species which invade bare area in a Ecological succession.
[The individual transitional communities are several stages further successive stages there will be a change in the diversity, increase in number of species and total biomass].

Types of ecological succession.

Question 37.
Distinguish primary’ succession with secondary succession?
OR
Write types of plant succession.
Answer:

Primary succession	Secondary succession
1. Starts where no living organism never existed organism existed.	1. Occurs in an area which have lost all living.
2. The establishment of a new biotic Community is generally slow.	2. Generally faster
3. It occurs on bare rock, cooled lava, newly created pond.	3. It occurs on abandoned form lands, burned/ cut forest, flooded lands.

[Note: As succession proceeds, the number and types of animals and decomposers also change.]

Question 38.
Why secondary succession faster than primary pressure?
Answer:
Secondary secession begins in an area where fertile soil and substratum are already present.

Question 39.
Distinguish between Hydrarch and Xerarch?
Answer:

1. Hydrarch succession: It takes place in water or wetter/ habitats and results in series of changes from hydric to mesic condition.
2. Xerarch succession: If plant succession takes place in dry area and results in changes from xeric to mesic condition.

Question 40.
Define Pioneer species? Give an example.
Answer:
The species which invade bare area in ecological succession are called pioneer species.
Ex: Lichens in Xerarch succession and phytoplanktons in Hydric succession.

Question 41.
Name the pioneer species in succession of hydric and Xeric?
Answer:

1. Phytoplanktons in water.
2. Crustose lichens on rocks.

Question 42.
Explain xerarch successionor?
Answer:

• Lichens the pioneer species invade (grown on) a bare rock since they are resistant to desiccation and high temperature
• Lichens secretes acids to dissolves rock, helping in weathering of rock and soil formation.
• The accumulation of soil and humus leads to growth of bryophytes and are capable of accumulating soil.
• The thick layer of soil with humus results in growth of herbs (place for seed for germination) and Trees.
• Ultimately a stable climax community is formed which ends up with Forest.

Question 43.
Explain hydrarch succession?
Answer:

1. Phytoplanktons are pioneer species consisting of unicellular colonial forms of green algae, followed by zooplanktons like amoeba, paramoecium, etc.
2. Death & decomposition of these planktons provide organic matter, which favours the growth of next plant stages.
3. Phytoplanktons are replaced by free floating angiosperms & then by rooted hydrophytes, sedges, grasses, & finally the trees.
4. The climax community remains in equillibrium stage, as long as environment remains unchanged.
5. The climax is a forest. It may be tropical deciduous or monsoon forests etc.

Question 44.
Mention the components of a succession in a Hydrosere?
Answer:

Question 45.
Define Nutrient cycling and Standing state?
Answer:

1. Nutrient cycling – The movement of nutrient elements through the various components of an ecosystem. It is known as biogeochemical cycles.
2. Standing state – The number of nutrients such as Carbon, Nitrogen, Potassium, Calcium etc. present in the soil at any given time.

Question 46.
Name 2 types of nutrient cycles along with examples?
Answer:

1. Gaseous – Eg: Nitrogen & Carbon cycle in atmosphere.
2. Sedimentary – Eg: Sulphur & Phosphorus cycle in Earth’s crust.

[Note: Environment factors like soil, moisture, pH, temperature regulate the release of nutrient into the atmosphere.
The reservoir helps to maintain imbalance in the rate of nutrient influx and efflux.]

Question 47.
What are biogeochemical cycles? Mention two types, with example.
Answer:
The movement of nutrient elements through the various components of an Ecosystem.
Two types:

1. Gaseous. Ex: Nitrogen/Carbon cycle.
2. Sedimentary Ex: Sulphur/Phosphorus cycle.

Question 48.
Give an example for gaseous cycle?
Answer:
Nitrogen cycle/Carbon cycle.

Question 49.
Give the schematic representation of carbon cycle?
Answer:

Question 50.
Explain carbon cycle (or) outline salient features of carbon cycling in an ecosystem.
Answer:
Explanation:

1. In Total quantity of global carbon, 71 % C is found dissolved in oceans and ocean regulates the amount of CO. in the Atmosphere.
2. Carbon cycling, involves atmosphere, ocean and through living and dead organisms.
3. 41013kg of carbon is fixed by photosynthesis annually.
4. Respiration activities of producers and consumers return carbon to the atmosphere as CO₂
5. Decomposers return back CO₂ during decor position of organic wastes and dead organic matter of land and oceans.
6. Another source of CO₂ is burning of fire wood, fossil fuels, combustion of organic matter, Volcanic eruptions, hot springs etc.
7. Some amount of fixed carbon is lost to Sediments and removed from circulation.

Question 51.
Why carbon cycle is known as perfect cycle?
Answer:
The carbon cycle is a perfect cycle, because the carbon is returned to atmosphere as soon as it is removed and circulated uniformly. [Rapid deforestation, burning of fossil fuel increase CO₂ cone, in atmosphere],

Question 52.
Explain Phosphorus Cycle?
Answer:

1. It is a sedimentary cycle and sediments of rocks are the reservoirs which contain phosphorus as phosphates.
2. Phosphorus is present in biological membranes, nucleic acids and cellular energy transfer system.
3. Animals shell, bones and teeth are made up of phosphorus.
4. During weathering of phosphate rocks, inorganic phosphorus is added to the soil and is absorbed by the roots of the plants.
5. Herbivores and other animals obtain this element from plants.
6. The waste products and the dead organisms are decomposed by phosphating Bacteria and add phosphorus to the soil.

Question 53.
Why phosphorus cycle is known as imperfect cycle?
Answer:
Phosphorus cycle is imperfect cycle because the biological processes account for considerable loss of phosphorus form the cycle.

Question 54.
Differentiate between Carbon and Phosphorus cycle?
Answer:

Carbon Cycle	Phosphorus cycle
1.Atmosphere is the reservoir of carbon.	1. Earth’s crust is the reservoir of Phosphorus.
2. It is perfect cycle.	2. It is imperfect cycle.
3. Gaseous exchange between organism and environment is more.	3. Gaseous exchange between organism environment is less.
4. Respirator release of Carbon to atmosphere.	4. No respiration release of Phosphorus.

Question 55.
Define Ecosystem services?
Answer:
“The products formed in ecosystems are named as Ecosystem Services.”

Question 56.
List few ecosystem services?
Answer:

1. Healthy forest ecosystems purify air and water, mitigate droughts floods, cycle nutrients, maitain fertile soils, provide wild life habitat.
2. Maintain biodiversity, pollinate crops. Storage site for Carbon.
3. Ecosystem provides aesthetic, cultural and spiritual values.

Note: Robert Constanza has put an average price tag of US 33 trillion a year on their ecosystem services which is nearly twice the valve of global gross national product Gross National Productivity (GNP). (18 trillion).

→ Succession in Plants:
Based on the nature of habitat it is classified as Hydrosere and Xerosere or Hydrarch and Xerarch.

2nd PUC Biology Important Questions with Answers

Karnataka 2nd PUC Biology Important Questions Chapter 13 Organisms and Populations

Question 1.
Define Ecology?
Answer:
Study of interactions, between organisms and their abiotic environment.

Question 2.
Mention the 4 levels of biological organisation?
Answer:
“Ecology studied under 4 different levels of biological organisation.

1. Organisms
2. Populations
3. Community
4. Biome.

Question 3.
What is biome? Mention major biomes of India?
Answer:
Biomes are very large ecosystems, characterized by major vegetation type, Ex: desert, tundra, grass lands etc.

Question 4.
Define Habitat?
Answer:
It is a specific place where species or specific population lives in nature.
[Abiotic factors like temperature, water light and soil along with biotic factors, pathogens, predators, parasites microbes characterize the habitat of an organism].

Question 5.
Explain any three type major abiotic factor influencing the life of organisms.
(b) Name the type of interaction in the following organisms
(i) Fungi-Roots of higher plants
(ii) Cattle-Egret
(iii) Cuckoo-Crow.
Answer:
(a) Temperature: Most ecologically important factor in the environment. The average temp decreases progressively from the equator towards the poles [which ranges from sub-zero in the polar region and more than 50°C in tropical deserts]

• Special, unique Hydrothermal vents have more than 100°C
• In organisms, metabolic activities depend on maximum and minimum temp. In different species, enzyme kinetics in the basal metabolism of an organism depends on temp.

(b) Water: Next to temperature, water is the most important factor which influences the life of organism “Elixir of life”. The productivity and distribution of plants are heavily dependent on water. For aquatic organisms quality [chemicals and pH of water] becomes important. Salt conc.like 5 in land water, 30-35 in sea and greater than 100 in some hyper saline lagoons.

(c) Light: Light responsible for – growth, development, of plants which are autotrophs. Many species of plants in forests are adapted to photosynthesis optimally under low light conditions, because they grow and are over shadowed by tall trees. Many plants require photo period (period of light) for flowering. [Short day, long day, day natural plants]. Animals to depend on light – for foraging, reproductive and migratory activities. Many marine algae and organisms are capable of absorbing certain colour components of the visible spectrum for their survival.

(d) Soil: Property of soil depends on the climate, weathering sedimentary or transported type water holding capability of soil, soil pH, mineral components and topography decides the type of vegetation in any area
which in turn supports different types of animals.
Ex: Benthic animals in water bodies.
(B)

1. Fungi – Root of higher plants. (Mycorrhiza).
2. Cattle – Egret (Commensalism).
3. Cuckoo – Crow (brood parasitism).

Question 6.
Give the significance of temperature on living organisms?
Answer:
(a) Temperature: Most ecologically important factor in the environment.
The average temp decreases progressively from the equator towards the poles [which ranges from sub-zero in polar regions and more than 50°C in tropical deserts].

Special, unique Hydrothermal vents has more than 100°C
In organisms, metabolic activities depend on maximum and minimum temperature. In different species, as enzyme kinetics in basal metabolism of an organism depends on temp. Different animals have different range of temperature tolerance.

Question 7.
Differentiate between Eurythermal and Stenothermal organisms with 2 examples.
OR
What are Eurythermal organisms?
Answer:

Eurythermal: A few organisms can tolerate and thrive in a wide range of temperatures. Eg: cat., dog, tiger etc.

Stenothermal: A few organisms (majority) can tolerate and thrive in a narrow range of temperatures. Eg: coral reefs, insects, seals etc.

OR
Explain the effect of water on life of oranisums?
Answer:
Water: Next to temperature, water is most important factor which influences the life of organism. ‘Elixir of life”. The productivity and distribution of plants is heavily dependent on water. For aquatic organisms quality [chemicals and pH of water] becomes important. Salt conc.like 5 in land water, 30-35 in sea &greater than 100 in some hyper saline lagoons. Based on the tolerance of salt, there are two type or organisms.

Question 8.
Differentiate between Euryhaline and Stenohaline organism give example?
Answer:

1. Euryhaline organisms: Tolerate a wide range of salinities (Salt cone).
   Eg: Avicennia, Salmon Eels.
2. Stenohaline organism: Which tolerates a narrow range of salinities(Salt cone).
   Eg: goldfish, freshwater. fishes.

Question 9.
Fresh water animals cannot live in seawater? Give reason?
Answer:
Many fresh water animals cannot live for long duration in sea water because of osmotic problem

Question 10.
Explain the effects of light and soil on vegetation?
Answer:
Light: Light responsible for – growth, development, of plants which are autotrophs.
Many species of plants in forests are adopted to photosynthesis optimally under low light conditions, because they grow in over shadowed by tall trees.

Many plants require photo period (period of light) for flowering. [Short day, long day, day natural plants]. Animals to depend on light – for foraging, reproductive and migratory activities.

Many marine algae and organisms are capable of absorbing certain colour components of the visible spectrum for their survival.

Question 11.
Name the components of the soil which decides types of vegetation?
Answer:
Soil: Property of soil depends on the climate, weathering sedimentary or transported type water holding capability of soil, soil pH, mineral components and topography decides the type of vegetation in any area which in turn supports different types of animals. Ex: Benthic animals in water bodies.

Question 12.
Define Homeostasis?
Answer:
Organisms have constant internal environment which could be in terms of constant temperature, osmotic cones
of body fluids. This maintenance of constant internal environment is Homeostasis. So, when there is variation in internal environment, organisms develop many adaptations to suit the conditions, following are important examples.

Question 13.
What are regulators? Give examples.
Answer:
REGULATE: Some organisms maintain homeostasis, by maintain constant body temperature, osmotic cone
etc. Ex: All birds, mammals, few vertebrates and invertebrates exhibits thermoregulation and osmoregulation to suit their environment, where they live.

In the case of Human being, body temperature is 37°c, when outside temperature is more, we sweat profusely. In winter in below 37°c, in shivering, a kind of exercise which produce heat and raises the body temperature. In plants it is absent.

Question 14.
What are Confonmers?
Answer:
CONFORM: Majority of animals and plants cannot maintain a constant internal environment and hence their body temperature [Conform = behave according to].
In aquatic animals the osmotic concentration of body fluid varies with ambient water osmotic concentration.

Question 15.
Why small animals are rarely found in polar regions?
Answer:
In case of small animals, they have a larger surface area relative to their volume and they tend to lose body heat very fast when it is cold outside, and they have to produce more energy to generate body heat through metabolism. This is the main reason why very small animals are rarely found in polar regions. If the stressful external conditions are localized or for short duration, organisms have other alternatives.

Question 16.
Explain the strategies by organisms to overcome the temporary stressful external conditions?
OR
Define migration with any 2 examples?
Answer:
Migration: The organism which can move away temporarily, from the stressful habitat to a more hospitable (comfort) area and return back when stressful period is over.
Ex: In every winter the famous keolado National park (Bharatpur) in Rajasthan will be place for Siberian birds, (cranes), coming from extremely cold Siberian Northern regions.
OR
Define suspension?
Answer:
Suspension: Different living organisms tide over very low or very high temperature conditions in various ways is known as suspension.
OR
What is Encystment? Explain with examples.
Answer:
Encystment: In bacteria, fungi and lower plants various kinds of thick walled spores are formed, to overcome unfavourable conditions prefer to germinate in favourable conditions. In higher plants seeds exhibit Dormancy.

In Euglena and Amoeba development of hard covering coat called cyst around their body to overcome unfavourable conditions which is known as encystment.
OR
What is Hibernation? Give example.
Answer:
Hibernation: (winter Sleep): It is the period of dormancy of some animals during winter, [ex: Bears escape in time]. Ex: Cold-blooded animals-Frog, lizards, etc.
Warm-blooded animals – Bear, Squirrel etc.
OR
What is Aestivation? Give examples.
Answer:
Aestivation (summer sleep) : It is a period of dormancy during summer related problems like heat and . dessication. Ex: Fish, Snails, Salamanders etc.
OR
Define diapause?
Answer:
Diapause: Under unfavourable conditions many Zooplanktons in lake ponds exhibits a stage of suspended development.

Question 17.
What is Adaptation? Explain relating to Kangaroo rat.
Answer:
It is any adjustment or attribute of an organism by having certain morphological, physiological or behavioural
response, which makes it to survive and reproduce in its habitat.
Ex: Kangaroo rat which lives in North American deserts is capable of meeting all its water requirements through fat oxidation cone, urine, where the minimal volume of water is used.

Question 18.
List the characters of desert plants?
Answer:
Thick cuticle on the leaf surfaces. Sunken stomata minimise water loss through transpiration
Special photosynthetic pathway tCrassulacean Acid Metabolism) enables their stomata to closed during day time. Opuntia and other desert plants have no leaves, they are modified into spines. Stems flattened, green and succulent and perform photosynthesis.

Question 19.
State Allen’s rule?
Answer:
According to Allen’s rule “mammals from colder climates have shorter ears and limbs to minimize heat loss”.

Question 20.
How are Seals adopted to live in polar areas?
Answer:
In polar areas aquatic mammals like seals have thick layer of fat [blubber] under their skin that acts as an insulator and reduces loss of body heat. .
ALTITUDE: In some organisms physiological adaptation are observed to respond quickly to a stressful situation. Ex: In man.

Question 21.
Define Altitude sickness? Mention the causes and symptoms of Altitudes sickness.
Answer:
When one moves to a high altitude place experience altitude sickness. “Altitude sickness is the physiological discomfort experienced by the individuals, when they are in high altitude due to low atmos pressure”. Altitude sickness symptoms includes Nausea fatigue ajid rest palpitation.

Because of low atmospheric pressure of high altitude, body does not get enough oxygen, then gradually adjust to the environment by increasing RBC production, decreasing the binding affinity of Hb and by increasing breathing rate. [Note: Most of the animals- narrow range of temperature [Human-37c], But Archaebacteria- live in hotsprings and deep sea hydrothermal vents(>100C temperature). Many Fishes – Antartic water (>0 temperature)

Organisms living in such an extreme conditions show a fascinating array of biochemical adaptations. Behavioural responses are exhibited by some organisms to adjust to variations in their environment].

Question 22.
How does desert Lizards manage their body temperature to in their environment?
Answer:
Desert lizards: They bask in the sun and absorb heat when their body temperature decreases and move to shade when temperature starts increasing. Some species are capable of burrowing into the soil to escape heat.

Question 23.
Define population?
Answer:
Population “The total number of organisms of a specific species present in a specific geographical area at a specific time”. [Note: Population has birth and death rates, The rates can be expressed in a change in numbers with respect to members of the population.
Examples:

1. last year – 20 lotus plants Reproduction – 8 plants are added
   Total = 28
   Birth rate = 0.4 of spring /year
2. Out of 40 fruit files, if 4 died, at a specific time (per week)]
   Death rate = 4/40 = 0.1 per week

Question 24.
Mention attributes shown by a population?
Answer:
Birth rate, Death rate , Sex ratio, Age distribution
[Note: Sex ratio: The no. of female and male per thousands individuals.

• Age structure: A population at any given time is composed of individuals of different ages.
• Age pyramid: “Age distribution is plotted for the population”]
• In a population, these age groups are identified – pre and post-reproductive, reproductive age groups

Question 25.
Explain 3 kinds of population?
Answer:
Expanding, Stable and declining population. The size of the population tells us a lot about its status in the habitat. To determine population size relative densities are measured. Ex: Bacterial culture in petridish, population size is determined indirectly without counting seeing them Eg: pug marks and faecal pellets in case of tiger in National parks.

Question 26.
Define population growth?
Answer:
It “refers to the increasing in population size”. [It is not a static parameter. The changes of density (Quantity) of population is due to four basic processes.]

Question 27.
List any characters that are employed in human population census? or Mention four basic processes that fluctuate the density of a population in a given habitat.
Answer:

1. Natality
2. Immigration
3. Mortality
4. Emigration

Question 28.
Define Natality, Immigration/Mortality(death rate)/Emigration? or Explain factors responsible for fluctuation in population density.
Or
Define Natality?
Answer:
IN umber of birth during a given period in the population that are added to the initial density
OR
Define Mortality?
Answer:
Number of deaths during a given period in the population.
OR
Define Immigration
Answer:
Immigration (I): Number of individual of the same species that have entered into the habitat from different places during a given period.
OR
Define Emigration?
Answer:
Emigration (E): Number of individuals of the population who left the habitat and gone to different place . during a time period under consideration.

Question 29.
Explain the equation of population density?
Answer:
If N is the population density at time ‘t’ then its density at time t + I is
N_t = N₀ + (B +1 – D + E)
N_t = N_t or + [(B + I) – (D + E)]
N_t = Final population size B = Natality rate
N₀ = Initial population size D = Mortality rate
I = Immigration rate E = Emigration rate population growth
= (Birth + Immigration) – (Deaths + Emigration).

Question 30.
Describe exponential growth with help of a population growth curve?
Answer:
Two types
1. Exponential growth: If resource (food and space) is plenty for an organism and no predators, shows this type of growth. Population grows exponentially till enough food is available after reaching the peak value the population may abruptly decrease to show a J-shaped curve.

If size population is N, the birth rate(b) and death rate(cf), then the increase and decrease in N during a unit time period will be (b – d) × N, let b – d = r, then = r × N [Intrinsic – basic character of an organism]. r = “Intrinsic rate of natural increase” of population growth based on biotic or abiotic factors.

The exponential or geometric growth results in a J shape curve, when plotted with N in relation time.
The integral form of Exponential – growth equation
N_t = N₀ + e^rt
N_t = Population density after time t
N₀ = Population density at time zero
r = intrinsic rate of natural increase
e = the base of natural logarithm (2.71828)

a – exponential growth curve
b – logistic growth curve.

Question 31.
Describe logistic growth?
Answer:
Logistic growth: A population growing in a habitat with limited resources slow initially a log phase (slow growth) followed by Exponential phase (accelerated growth) and finally stationary phase, when the population density reaches the carrying capacity(k).

Note: [A population growing in a habitat with limited resources leads to competition, and the fittest individual will survive and reproduce].

A plot of N in relation to time (t) results in a sigmoid curve. This type of population growth is called as Verhulst – Pearl Logistic Growth \(\frac{d N}{d t}\)= γN
where N = population density at time t
r = rate Intrinsic of natural increase
K = Carrying capacity
= Rate of change in population size
Since the resources for growth for most animal populations are unlimited and becomes limited soon or later the logistic growth model is considered a more realistic one.

Question 32.
What is carrying capacity?
Answer:
Maximum number of individual of a population, which can be supported with optimum resources of their survival.

Question 33.
What is Darwinian fitness? Give any 2 examples.
Answer:
“Population evolve to maximize their reproductive fitness called as Darwinian fitness(high r value), in the habitat in which they live”. They exhibit efficient reproductive strategy under particular set of selection pressures.

Example:
Organisms breed only once in life time – Salmon fish, Bamboo.
Many times – Birds and Mammals.
Production of a large number of small-sized offspring – Oysters, pelagic fishes.
Produce of small number of large-sized offspring – Birds and Mammals.

Question 34.
Mention the different possible interspecific interactions.
Answer:

Question 35.
Mention any FIVE population interaction with an example each
Answer:

Question 36.
Define predator?
Answer:
Predator: Organism which attacks, kills and feeds on other species. [An animal that naturally preys on others],

Question 37.
Define Prey?
Answer:
Animal that is hunted and killed by another for food is known as prey.

Question 38.
Write a note on significance of predators?
Answer:
Predation as natures way of transferring to higher trophic levels,” the energy” fixed by plants, so they are called as conduits. Predators control the growth and survival chances of prey population. Without predators prey species increase and causes ecosystem instability.

Predators may increase the biodiversity of communities by preventing a single species from becoming dominant.

Question 39.
Predators in nature are prudent why?
Answer:
If predator over exploits(over use) its prey, then the prey might become extinct and in turn predator also become extinct. That is the reason why predator in nature are ‘PRUDENT’ (wise) (Acting wisely).
[Note 1. When certain exotic species are introduced into a geographical area, they spread fastly since they does not have its natural predators].

Question 40.
How prickly pear cactus was controlled biologically?
Answer:
Prickly pear cactus introduced into Australia spreaded widely to million hectares.
It was controlled by cactus feeding moth (predator) which was bought from cactus origin(native) country.
[2. Biological control methods adopted to control agricultural pest based on the ability of predator to control prey pests],

Question 41.
Predators help in maintaining species diversity. Justify it?
Answer:
Predators help in maintaining species diversity in a community, by reducing competition
Ex: Starfish pisaster is an important predator in intertidal communities of American Pacific Coast. In a experiment conducted in sea, when all the starfish were removed, more than 10 species of invertebrates became extinct within a year because of inter specific competition.

Question 42.
How do some species of insects and Frogs avoid being detected by predators?
Answer:
Prey species have evolved to avoid Predators.
Ex: Camouflage (a) Some frogs and insects are cryptically coloured to avoid being detected easily by Predators.
(b) Some species are poisonous to avoid Predators. Ex: Monarch butterfly is highly distasteful to predator bird. This distaste is due to chemical present in the body which is acquired during their caterpillar stage by feeding on a poisonous weed.

Question 43.
How do some plants species avoid herbivores?
Answer:
Plants (prey) avoid herbivores (predators),& phytophagous insects which feed on plants and other parts. Since plants are stationary they have evolved different morphological and chemical defences against herbivores.

Ex: Thoms in Acacia & Cactus.
Chemicals in Calotropis produces poisonous cardiac glycosides where this avoids cattle or goats browsing on them; Various plant extracts which are used as chemical substances like Nicotine* Caffeine, Quinine, opium, strychnine are plant alkaloids produced in plants as defence mechanism against predators.

Question 44.
Define Competition?
Answer:
“Competetion it is An interaction that occurs between two or more organisms for the same necessary resources”

Question 45.
According to Darwin which is the potent force in organic evolution?
Answer:
According to Darwin interspecific competition is a potent force in organic evolution.

Question 46.
Some times totally unrelated species could compete for the same resource? Give examples.
Answer:
Ex: Flamingo birds and Fishes complete for their common food Zooplanktons in South American lakes. Some times the feeding efficiency of one species might be reduced, due to interference of other species even if resources are abundant. [Where competition  fitness of one species will become lower in the presence of other species]

Question 47.
State Gause’s competitive exclusion principle? Give example.
OR
State Gause’s competitive exclusion principle.
Answer:
Cause (1934) p0 forwarded principle, which states that “two closely related species competing for the same resources cannot co-exist indefinitely and competitively inferior one will be eliminated eventually.
Example of competitive exclusion:

1. Abingdon tortoise in Galapagos Islands become extinct within a decade after goats were introduced in to the island due to great browsing efficiency of Goats.
2. Elimination of smaller barnacle chthamalus by superior barnacle Balanus on the rocky sea costs of Scotland.
   [Note: Recent studies do not support this generalization about competition, and but point out that species facing competition might evolve and promote co existence instead of exclusion.].
   Ex: Me Arthur showed that five closely related species of warbler’s (singing birds) living on the same tree.

Question 48.
Define Parasitism?
Answer:
It is an interaction or association between two living organisms, in which one species (smaller) called Parasite gets its food and shelter from another living organism (larger) called Host.

Question 49.
Write a note on Parasitic adaptation?
Answer:

• Loss of unnecessary sense organs, loss of digestive system.
• Presence of adhesive organs or suckers.
• High reproductive capacity.
• Complex life cycle
  Ex: 1. liver fluke requires two hosts snail and a fish.
  2. Plasmodium-Mosquito and mar:
• Harmful effect on host: harm the host, reduce life span of host, lastly reduces its population.

Question 50.
Differentiate between Ecto and Endoparasites with examples?
Answer:

Ectoparasites	Endoparasites
1. They feed the external surface of the host	1. They live inside the host body at different sites
2. The life cycle is simple	2. The life cycle is complex
3. Ex: lice on humans, ticks on dogs, cuscuta plant on hedge plants	3. Ex: Plasmodium in RBC of man, Round and Tape worms in the guts of man.

Question 51.
Explain brood parasitism with an example?
Answer:
The parasitic birds lay its eggs in the nest of the host and lets the host incubate them is known as brood parasitism. During the course of evolution the eggs of parasitic bird have evolved to resemble host’s egg to reduce file chances of detecting the foreign eggs and ejecting from the nest. Ex: Cuckoo (koel) lays its eggs io crow’s nest.

Question 52.
Whatis Commensalism? Give an example.
Answer:
“Interaction in which one species is benefited and the other is neither harmed or benefited.
Ex: Epiphytic orchids growing on Mango and other trees.
Barnacles on back of whales. Cattle Egret and grazing cattle (Egrets get insects) clown fish living among tentacles of sea anemone (fish protected), sucker fish and shark.

Question 53.
Define Mutualism? Give examples.
or
Mutualism is a method of population interaction? Explain with examples.
Answer:
Association between two species, and both species are benefited.
Examples:

1. Lichens with fungi and algae or cyanobacteria Fungi – help in the absorption of nutrients from the soil.
   Algae – provides carbohydrates to fungi.
2. Mycorrhizae with fungi and root of higher plants.
   Fungi – Help plants in absorption of nutrients.
   Plants provides carbohydrates to fungi.
3. Plants and pollinators, seed dispersal agents.
4. Fig provide food to wasp, wasp pollinate the fig inflorescence.

Question 54.
Explain co-evolution with a suitable example?
Answer:
Fig and wasp: Fig flower is pollinated by its only one pollinator wasp species. The wasp uses the Fig as an
Oviposition, in turn, pollinates. Fig provides fruit and seeds for nourishing larvae.

Question 55.
Explain sexual deceit as an interaction of species with an example?
Answer:
Mediterranean Orchid Ophrys employs ‘sexual deceit’ to get pollination done by a species of bee. One petal of the flower resembles female bee which attracts male bee to the flower and pseudo copulates which effects pollination. When this same bee pseudocopulates with another flower, it thus pollinates the flower.

Question 56.
Define Ammensalism with an example?
Answer:
Association between two species that is harmful to one of the species, but no effect on the other (niether benefited nor harmed) Ex: Certain plants release toxins that inhibit the growth of other plant species.

→ Ecology – Ernst Haeckel (1869) coined the term Ecology
Oikos = home/place logos = study.

→ Organism And Its Environment:
Variations in temperature, seasons together with variation in precipitation (rain and snow), leads to the formation of major biomes-Desert, Rain forest, Grasslands and Tundra. Changes in each biome lead to the formation of a wide variety of Habitats.

→ Growth Models Or Curves:
Growth of population can be expressed by a mathematical expression called growth curve in which total number of individuals in a population is plotted against time.

→ Population Interactions:
Populations of different species often interact with each other in various possible ways in their habitats. These interactions may be beneficial, neutral or detrimental.
Sign ‘+’ = beneficial interaction
‘-‘ = detrimental interaction
‘o’ = Neutral interaction
The possible outcomes of possible interspecific interaction are shown in the table.

2nd PUC Biology Important Questions with Answers

Karnataka 2nd PUC Biology Important Questions Chapter 12 Biotechnology and its Applications

Question 1.
What are the major critical research areas of Biotechnology?
Answer:
Three critical research areas of Biotechnology

1. Providing the best catalyst in the form of the improved organism.
2. Creating optimal conditions, through engineering for catalyst.
3. Downstream processing technology to purify the protein/organic compound. ,

Question 2.
What are genetically modified organisms? Mention their significance.
Answer:
An organism developed by introducing a desired foreign gene is Genetically modified organisms.
Ex: Bt Cotton, Bt Brinjal, Bt Soyabean

Significance of Genetically modified organisms (GMO):

• Made crops tolerant to heat, cold, salt, drought stresses.
• Reduced reliance on chemical pesticides.
• Reduce post-harvest losses.
• Increased efficiency of mineral usage by plants.
• Enhanced nutritional value of food.
• Pest resistant plants.

Question 3.
Mention any two advantages of GMO’s?
or
In which way genetically modified plants are useful?
Answer:
Significance of Genetically modified organisms (GMO):

• Made crops tolerant to heat, cold, salt, drought stresses.
• Reduced reliance on chemical pesticides.
• Reduce post-harvest losses.
• Increased efficiency of mineral usage by plants.
• Enhanced nutritional value of food.
• Pest resistant plants.

Question 4.
What are genetically modified organisms? Name two Bt toxin-producing plants?
Answer:
An organism developed by introducing a desired foreign gene is Genetically modified organisms.
Ex. Bt Cotton, Bt Brinjal, Bt Soyabean.

Question 5.
Which soil bacteria produces Bt toxin?
Answer:
Bt- Bacillus thuringiensis – bacterium

Question 6.
Name the protein produced by Bacillus thuringiensis?
Answer:
Protein produced – Crystal protein

Question 7.
Write a note on Bt toxin? One of the applications of biotechnology is the product on of insect resistant
crop plants just by the statements with reference to Bt cotton?
Answer:
Insecticide crystal protein is produced by Bacillus thuringiensis nontoxic to itself (inactive protoxin), if this protoxin is ingested by insect, it is converted into an active toxin form, due to alkaline pH of the gut, which solubilise’the crystals.

The activated toxin binds to the surface of epithelial cells in midgut and create pores, then cause swelling and lysis and eventually cause death of the insect.Thus cotton plant is protected from bollworm .
[Note: The choice of genes depends upon the crops and targeted pest. Toxins are encoded by cry gene.]

Question 8.
Name any two forms cry gene of Bt cotton.
Answer:

1. cry I Ac, cry II Ab, cry I Ab.
2. Control of Nematode parasites – Pest resistant plants

Question 9.
Name a nematode which infects tobacco plants and explain how it is controlled? (5M)
Answer:
Ex: Meloidegyne incognitia – infects the roots of tobacco plants, leads to reduction in the yield.
Control by process- RNA interference (RNAi):

• RNA i – In eukaryote’s plays a role of cellular defence involves silencing mRNA, by complementary is RNA , which binds & prevents translation of m RNA of the pathogen.
• Using Agrobacterium as vector, nematode specific genes were introduced of RNA in host.
• Introduction of DNA was such that, it produces both sense and antisense RNA in host cells, which formed ds RNA.
• This dsRNA intiates RNAi, by binding to mRNA and prevents translation of mRNA(silencing) of pathogen. Now plant is protected from the parasite Nematode.

Question 10.
Give an account of genetically engineered Insulin?
Answer:

• 1. Insulin consists of short polypeptide chains * A-chain (21 amino acids) (acid chain)
• B-chain (30amino acids) (Basic chain) which are linked together by disulphide bridges.
• In mammals including humans, insulin is synthsised as a proinsulin, which has a single long chain of amino acid. This proinsulin has an extra chain (connecting chain) which is removed during maturation of proinsulin to insulin.

Using recombinant DNA technology Eli lilly (1983) American company prepared chemically synthesised DNA sequence of A and B chain of insulin separately and introduced into plasmids of E. Coli to produce insulin chains. Purified A and B chains were extracted and combined by creating disulphide bonds to form human insulin ‘Humulin’.

Question 11.
Name the first man made insulin?
Answer:
Humulin.

Question 12.
Define Gene therapy? Give an example. OR Name the disorder to which clinical genetherapy was given first.
Write a note on Gene therapy? How ADA deficiency cured by genetherapy.
Answer:
It is a technique of replacing defective gene by normal function gene to correct congenital defects (embryo/ child). Ex: SCID.

The first human gene therapy trial was tried on August 14(1990)on a 4-year old girl with Adenosine deaminase (ADA) deficiency, which causes genetic disease 1 ’severe combined Immune deficiency” (SCID).

ADA enzyme is crucial for the immune system to function . If deleted or impaired it causes SCID.[T-lym- phocytes (immune cell) from bone marrow which gets originate and get differentiated in Thymus (bilobed structure above the heart in thorax)].

It can be cured by patient lacking functioning of T-lymphocytes and ADA gene. By bone marrow transplanta¬tion or Enzyme replacement theory (i.e. ADA).

Question 13.
Why ADA deficiency treatment recurrent in nature?
Answer:
One disadvantage from these cells, is that, these cells are not immortal have with short life span.Repeated genetically engineered lymphocytes injections has to be given to the patient, to control disease.

Solution: If the ADA gene is isolated and introduced into cell at early embryonic stages it could be a permanent cure.

Question 14.
Explain the Molecular diagnosis techniques.
Answer:
The effective treatment of disease requires, early diagnosis and understanding its pathophysiology. ‘Earlier discuss was diagnosed by serum, and urine analysis, but this was not useful for early detection.

• So, modem techniques like, Recombinant DNA technology ELISA (Enzyme-linked Immuno Sorbant assay) are used.
• Infection of pathogens (Viruses and bacteria) can be early detected by amplification of their nucleic acid by PCR, even when the symptoms of the disease are not yet visible.
• PCR is used to detect HIV in suspected AIDS patients and other genetic disorders.
• ELISA test is based on the principle of antigens or by antibodies produced against pathogen.

Question 15.
What are transgenic animals? Give examples.
Answer:
Animals that have DNA that is manipulated to possess and express an forcing gene.Ex: Transgenic Rabbit, Sheep, cows.

Question 16.
Explain significance of transgenic animals?
Answer:
1. Normal physiology and development: Transgenic animals allow us to study, how genes are regulated, and
their affect on the normal function of the body and its development and, to study biological role of genes in the body. Ex:synthesisof Insulin.

2. Study of disease: They are produced to understanding the role of in the development of diseases like cancer, cystic fibrosis, rheumatoid arthritis etc.

Question 17.
Write a note on biological products in transgenic animals?
Answer:
Biological products: They replace expensive biological products which were used as medicine.
They can be created by introduction of the portion of DNA, which codes for particular protein.
Ex: human protein a-I Antitrypsin is used to treat Emphysema [swelling of alveoli, later destroyed] to treat phenylketonuria [Mental retardants due to autosomal gene mutation], –

1. To treat cystic fibrosis [hereditary disease, of exocrine gland thick mucus blockage of pancreatic duct, bronchial respiratory infection],
2. Babies (Human) can be given nutritional enriched milk, than natural cow milk.
3. In 1997 the first transgenic cow Rosie produced, to have human protein enriched milk [24g/It], [for this several human gene were successfully transferred in cows, expressed in the mammary tissues and produced milk which contained alpha-lactalbumin which in present in human],
4. Vaccine Safety testing: Vaccines are either dead or living weakened microorganisms administered to man or animals to stimulate immunity to infection, so they are protected against infections later.
   Before they are given, safety of vaccines must be tested, for this Transgenic mice are being used to test vaccine safety Ex: polio vaccine.
5. Chemical safety testing: Transgenic animals are more sensitive to toxic substances than non transgenic animals. If they are exposed to toxic substances, non transgenic animals, exhibit toxic symptoms but not in transgenic animals. This help us to obtain the results faster.

Question 18.
What is emphysema? Name the recombinant protein to treat it?
Answer:
(a) Emphysema is a chronic lung disease caused by damage to aveoli in smokers.
(b) Recombinant protein is α-I Antitrypsin.

Question 19.
Name the first transgenic cow?
Answer:
Rosie.

Question 20.
Which vaccine was being tested on mice?
Answer:
Polio vaccine.

Question 21.
Expand GEAC?
Answer:
Genetic Engineering Approval Committee.

Question 22.
Define patent? Give examples of patented crops.
Answer:
PATENT: A contract between society and an inventor. It is a set of exclusive rights granted by a govt to inventors and prevents others making selling or importing given inventions.

Public anger towards granted patents for products that are indigenous to a specific country.
Eg: Basmati rice is indigenous to India, but American companies got patent right on this rice variety basically it was a cross between Indian Basmathi and semi-dwarf varieties.
[Ex: Neem, Turmeric],

Question 23.
Write a note on biopiracy?
Explain it with reference to Basmathi rice.
Answer:
Biopiracy is a use of bioresources by multinational companies and other organisation without getting ” authorization from the countries and people concerned without compensatory payments. [It is robbery or theft biological and genetic resources indigenous to a country].

Ex: Basmathi rice is unique for its aroma and flavour and 27 varieties are grown in india .

An American company got patent right and allowed the company to sell a new variety of Basmati in abroad
Basically new variety was derived from India farmers Americans crossed the Indian Basmathi rice with semi dwarf of varieties and claimed as their own invention and other people selling Basmathi is restricted by their patent.

Question 24.
What is biopiracy?
Answer:
Use of bioresources by multinational companies without authorisation.

→ The applications of Biotechnology includes therapeutics, diagnostics, GMO, Bioremediations, waste treatment and energy production.

→ Applications in Agriculture:
There were three options for increased food production. Agrochemicals, organic agriculture and Genetical engineered crop based agriculture. The green revolution succeeded in tripling he food supply but yet not enough to feed the growing population. GM crops are possible solutions to minimize the use of fertilizers and chemicals.

→ Bio Technological Application in Medicine:
The recombinant DNA tech has made a great contribution to medicine and enabled mass production of safe and more efficient drugs. At present (30)drugs are produced, of which (12) are marketed in India.

→ Genetically Engineered Insulin:
Insulin – human protein, produced by Islet of Langerhans of pancreas.
Maintain carbohydrates level in the blood:
Deficiency causes Hyperglycaemia and excess glucose is excreted through urine causing Diabetes mellitus. Patients were previously treated with insulin tablets or injection obtained from pancreas of slaughtered cattle and pigs, since Insulin was from animal source,and caused Allergy in some patients, now the Insulin is produced through Recombinant technology using E, coli.

→ Early Gene Therapy Experiments:
T-lymphocytes were extracted from the bone marrow of (blood) SCID patient:

• They are grown in culture outside the body.
• Functional ADA -adenosine deaminase gene is introduced into these cells with help of retro virus as a vector.
• These engineered cells are injected to bone marrow of patient where cells multiply and produce enough ADA to relieve the disease symptoms.

→ Ethical Issues (Moral Rights):
Genetic engineering – raises questions related to hazardous effects of organisms and, products safeguards to be adapted regarding this.

Ethical issues/standards must be there to evaluate all human activities and the biological significance of organisms when introduced into the Ecosystem.

Their fore Govt, of India, has set up Genetic Engineering Approval Committee (GEAC) of MoEF- to take the decision on validity, the safety of GMO (Genetically Modified Organisms) research and organism for public services.

2nd PUC Biology Important Questions with Answers

Karnataka 2nd PUC Biology Important Questions Chapter 11 Biotechnology: Principles and Processes

Question 1.
Define Biotechnology.
Answer:
Term coined by Karl Esky (1919). “The utilisation of living organisms or their components for the welfare of mankind.”
Definition: according to European Federation of Biotechnology (EFB). “The integration of natural science and organisms, cells, parts, molecules for products and services”.

Two techniques that established Biotechnology

Question 2.
Define genetic Engineering?
Answer:

1. Genetic Engineering: Technique which alters the chemistry of DNA to introduce altered DNA into the host
   organisms to change their phenotype.
2. Sterile Environment: Contamination free environment to enable the growth of the desired microbes, cells, vaccines, enzymes in large quantities for their products.

The technique of G.E includes:

• Creation of Recombinant DNA
• Production of multiple and identical copies of a selected gene – Gene cloning
• Transfer of gene into another cell.

Question 3.
Mention two techniques that established biotechnology?
Answer:
Genetic engineering and sterile environments. [The first Rec-DNA was constructed by Stanley Cohen and Her-best Boyer (1972), by linking an (antR) antibiotic resistance gene with the natural plasmid of salmonella.]

Question 4.
Define plasmid? or What are plasmids?
Answer:
Autonomously replicating, circular, extrachromosomal DNA, found in the cytoplasm of Bacteria.

Question 5.
Mention the basic steps in GMO.
Answer:
Basic steps in Genetically modifying organisms (GMO)

1. Identification of gene in DNA with desirable character
2. Insertion of that gene into plasmids.
3. Introduction of recombinant plasmids into host cells.
4. Maintainance of the introduced gene in the desired organism and transfer of DNA into its progeny.

Question 6.
Who discovered Rec-DNA technology?
Answer:
Stanley cohen it Erbert boyer.

Question 7.
Name the molecular scissor, used in recombinant DNA technology?
Answer:
Restriction Endo Nuclease.

Question 8.
Name the enzyme used to cut DNA strands?
Answer:
Restriction Endo Nuclease.

Question 9.
Mention the tools used in Rec. DNA technology.
Answer:
Restriction on Endo Nuclease, ligases, DNA polymerase.

1. Enzymes
2. Cloning vectors
3. Competent host
4. Desired gene
5. Bioreactor.

Question 10.
Who isolated REN for the first time?
Answer:
Hamilton Smith (1970), RENHind II from Haemophilus influenzae.

Question 11.
To which group of enzymes REN belongs?
Answer:
REN belongs to a larger class of enzymes – Nucleases.

Question 12.
What are Exo and endonucleases? or classify restriction enzymes. Mention the function of each.
Answer:

• Exonucleases Remove nucleotides from the ends of the DNA.
• Endonucleases Remove nucleotides at specific positions in the middle of the DNA.

Question 13.
How’REN named?
Answer:
Naming REN, Principles:

• Three letter code is given for each REN. The first letter represents the genus name of Bacteria with a capital letter and the subsequent two letters with the small letter will be the species name.
• Ex: Eco, Hin etc., Next letter represents the strain, and the roman number indicates the order in which the enzymes were isolated from the same organism.
• Ex: Hind III Eco RI Bam HI.

Each REN cut DNA at specific 4 to 6 base pairs sequence known as Palindrome Sequences

Question 14.
What are palindrome sequences. Give an example?
Answer:
Two strands in this region are identical when read both in forward and backward on two DNA strands
Ex:

Question 15.
What are sticky ends?
Answer:
REN cut in palindrome site between the same 2 bases on opposite strands which leave single stranded portion at the ends – These single stranded free ends which can join with similar complementary ends of DNA fragment from other source are knows as “Sticky ends”.

Question 16.
Write the function of DNA ligase.
Answer:
Joins DNA fragments.

Question 17.
Give a diagrammatic representation of showing the action of restriction enzyme in the formation of recombinant DNA?
Answer:

1. Steps in formation of recombinant DNA by action of restriction endonuclease + enzyme-EcoRI
2. Ligase: Enzyme facilitates the joining of DNA strands catalyzing the formation of an inter-nucleotide ester bond between phosphate and deoxyribose. i.e. phosphodiester bond
3. Polymerase: DNA polymerase synthesis new strands of DNA complementary to existing DNA.

Question 18.
Draw a neat labelled diagram of agarose gel electrophoresis?
Answer:

A typical agarose gel electrophoresis showing migration of undigested (lane 1) and digested set of DNA fragments (lane 2 to 4).

Question 19.
Explain in brief the separation and isolation of DNA fragments?
Answer:
The cutting of DNA by REN results in fragments of DNA, which is separated by ‘Gel electrophoresis. Since DNA fragments are negatively-charged molecules, they move towards anode, under an electric field through a medium [Agarose gel].

DNA fragments move according to their size (smaller farther and larger near), eparated DNA fragment can be visualised only after staining DNA with ‘Ethidium bromide. ’ Orange bands of >MA seen only under “EFV light.” The separated DNA fragments are cut out from the agarose gel and extracted am gel piece – Elution. The eluted DNA fragments are purified and used in constructing recombinant DNA by joining them with cloning vectors.

Question 20.
What is Elution?
Answer:
The separated DAN fragments are cut out from the agarose gel and extracted from gel piece

Question 21.
Name the stain used for visualising DNA under UV radiation?
Answer:
Ethidium bromide.

Question 22.
Mention the technique used to separate DNA fragments in or DNA technology?
Answer:
Agarose gel electrophoresis.

Cloning Vectors:
Cloning Vector: Vectors that are used for the propagation of DNA of interests in a suitable host cell, Eg: Plasmids, Bacteriophage.

Structure of Plasmid:
William Hay and Laderberg (1952) discovered plasmid.
PBR 322 – Naturally occurring plasmid
[Plasmid of Boliver and Rodriquez,’strain 322],

Question 23.
What is plasmid? Mention two sites of plasmid.
Answer:
Plasmids are extra Chromosomal self replicating circular DNA molecules present in the cytoplasm of bacteria

Two sites:

1. Origin of replication (ori): Sequence of nucleotides from where replication starts. If any piece of DNA linked to this site, can be made to replicate within host cells.
2. Selectable Marker: The vector requires a selectable marker to identify and eliminate non- transformants, and allow the growth of transformants. Transformation is a procedure through which a piece of DNA is introduced into a host bacterium. Ampicillin, Tetracyclin are useful selectable markers.

Question 24.
Describe the structure of the plasmid?
OR
Explain the features of cloning vectors?
Answer:

1. Origin of replication (ori): Sequence of nucleotides from where replication starts, if any piece of DNA linked to this site, can be made to replicate within host cells.

2. Selectable Marker: The vector requires a selectable marker to identify and eliminate non- transformants, and
allow the growth of transformants. Transformation is a procedure through which a piece of DNA is introduced into a host bacterium Ampicillin, Tetracycline is useful selectable markers.

3. Cloning sites: The vector should have single or few recognition sites for REN, to insert foreign DN A, which
is ligated at a restriction site present with in the marker gene. Ex: Bam HI or sal I which lie in TetR gene PVU I or Pst I which lie in AmpR gene.

When the genes are inserted into marker gene [eg. TetR gene] the recombinant, plasmids will loose tetracycline resistance, when these plasmids cultured on medium containing Tetracycline will not grow, but grow on medium with Ampicillin.

Therefore recombinants and Non-recombinants can be differentiated.

Above process was time-consuming, so the alternative method was developed, where markers can be differentiated on basis of producing colour in the presence of chromogenic substrate.

Question 25.
What is insertional inactivation?
Answer:
In this process, if a rec-DNA is inserted within coding sequence an enzyme of a plasmid, i.e., p galactosidase
causes inactivation of the enzyme – “Insertional inactivation.”

Thus recombinant -colonies are identified.
i. e. non inserted p – gal produces no blue colour, blue colonies produced are identified as recombinant colonies.

Vectors For Cloning Genes in Plants And Animals:
To deliver genes in Eukaryotic cells. [A agrobacterium tumefacient is a – soil bacteria, pathogen on dicot plants, causes crown gall disease forming Tumours.]

Question 26.
Which in common vector is used for cloning genes in plants?
Answer:
Agrobacterium tumefacians.

Question 27.
Describe the role of Agrobacterium tumefaeians in cloning vectors in plant and animal cells?
Answer:
Agrobacterium tumefacians is able to decliver TDNA which transform normal cells into tumour cells to produce chemicals required by pathogens. So these Tumour inducing plasmids (Ti) are genetically modified and then bacteria is allowed to infect dicot plant cells and induce tumour formation, which indicates transfer of desired gene, and these vectors are made non pathogenic to deliver genes in plant cells.

Question 28.
Define Retroviruses?
Answer:
Retroviruses – RNA viruses, replicate through reverse transcriptase (RNA synthesising DNA), and made non-pathogenic, then used to deliver genes in animal cells.

Question 29.
“Retroviruses are disarmed before using to deliver desirable genes into animal cells. Why?
Answer:
Retrovirus may cause harm to host cell so disarming helps retrovirus in insertion of desirable genes into animal cell.

Competent Host (Right Host) (Capable):
Since DNA molecules can not pass through cell membrane, host cells are made competent to take up DNA.

Question 30.
Describe methods involved in making a competent host?
or
Mention two techniques or make host competent in r-DNA technology?
Answer:

1. By treating with divalent cation, which increases the efficiency of DNA to enter through pores in the cell wall.
2. By incubating cells with Rec-DNA on ice-cold CaCl, followed by placing them at 420°C (heat shock) and again back to ice, which developers pores.
3. Microinjection: Recombinant, DNA directly injected into the nucleus of animal cell using Microsyringe.
4. Gene gun (Biolistics): Suitable plant cells are bombarded with high-velocity microparticles of Gold or tungsten coated with DNA in plant cells.
5. Disarmed pathogen vectors, when allowed to infect the cell and transfer the rec- DNA into the host.

Question 31.
What are Biolistics or Gene gun?
Answer:
Plant cells are bombarded with high-velocity microparticles of gold or tungsten located with DNA.

Question 32.
Give diagrammatic representation of processes of Rec. DNA technology?.
Answer:

Question 33.
Explain the steps involved in rDNA technology.
Answer:
It is essential to isolate DNA in pure form, so the cell is broken open to release DNA along with other molecules, so treated with enzymes like.

• Lysozyme for Bacteria
• Protease – for Proteins
• Cellulase for Plants
• Ribonuclease – for RNA
• Chitinase for Fungus

Finally, the purified DNA molecules are precipitated after the addition of chilled Ethanol can be seen as a collection of fine threads in the suspension.

Cutting of DNA:
By REN. DNA molecules are incubated with REN where the progress of this process is checked by Agarose gel Electrophoresis. Gene of interest and cut vector are mixed and ligase is added to produce rec. DNA.

Amplification of Gene:
The process of making many copies of a gene by polymerase chain reaction is known as DNA amplification
(a) Denaturation: Reaction mixture when led to a temp 90-98°C results in separation of two strands of DNA, which acts as template strands for DNA
(b) Annealing: Reaction mixture is cooled at a low temp (40-60°C). two oligonucleotides primers anneal (join) one at each 3’ end of DNA strand.
(c) Primer Extension: Taq DNA polymerase [Enzyme DNA polymerase from Thermus aquaticus bacteria [which is thermostable] extend primers, using nucleotides and DNA templates. The amplified fragment if desired can now be used to ligate with vector for gurther cloning.

Obtaining the foreign gene product:
Recombinant plasmids under proper conditions expressed and synthesise desired proteins and these proteins are separated and purified by following technique i,.e ‘protein encoding gene is expressed in a heterologous host’ which forms Recombinant protein.

Question 34.
How is DNA isolated from cell. Give any 2 examples of enzymes.
Answer:
It is essential to isolate DNA in pure form, so the cell is break open to release DNA along with other molecules, so treated with enzymes like,

• Lysozyme for Bacteria
• Protease – for Proteins
• Cellulase for Plants
• Ribonuclease – for RNA
• Chitinase for Fungus

Finally the purified DNA molecules are precipitated after addition of chilled Ethanol, can be seen as collection of fine threads in the suspension.

Cutting of DNA:
By REN. DNA molecules incubated with REN where the progress of this process is checked by Agarose gel Electrophoresis. Gene of interest and cut vector are mixed and ligase is added to produce rec. DNA.

Question 35.
Define polymerase chain reaction.
Answer:
It is a process in which gene is amplified into several copies using DNA polymerase.

Question 36.
What is DNA amplification. Mention the steps in PCR technique.
Answer:
The process of making many copies of gene by polymerase chain Reaction is known as DNA amplification
(a) Denaturation: Reaction mixture when led to a temp 90-980C results in separation of two strands of DNA, which acts as template strands for DNA synthesis.

(b) Annealing: Reaction mixture is cooled at a low temp (40-60°C). two oligonucleotides primers anneal (join) one at each 31 end of DNA strand.

(c) Primer Extension: Taq DNA polymerase [Enzyme DNA polymerase from Thermus aquaticus bacteria [which is thermostable] extend primers, using nucleotides and DNA templates. The amplified fragment if desired can now be used to ligate with vector for further cloning.

Question 37.
Name the source of Taq polymerase.
Answer:
Thermus aquaticus bacteria.

Question 38.
What is Annealing.
Answer:
During PCR technique, the reaction mixture is cooled to 40~450°C and 2 Oligonucleotide primers join at each ends of separated DNA.

Question 39.
What is primer extension.
Answer:
During PCR Taq DNA polymerase extends primers using nucleotides and DNA templates.

Question 40.
Draw a neat diagram of stirred tank bioreactor or Sparged tank Bioreactor? or Simple stirred tank Bioreactor?
Answer:

Bioreactor: Container in which substances are treated to stimulate biochemical transformation by microorganisms or enzymes. “Large vessel in which raw materials are biologically converted into specific products using plants/ animal/human cells. The large scale production is carried out in Bioreactor.

A stirred-tank bioreactor is usually cylindrical or with a curved base to facilitate the mixing of the reactor contents. Stirrer facilitates even mixing and O₂ availability throughout, and alternatively, air can be bubbled. Aeration and agitation generate foam, which prevents flow of contents, antifoam controls foam. Temperature control system and pH control system and sampling ports are present, so that small volumes of the culture can be withdrawn periodically.

Question 42.
Mention the different steps of process of recombinant DNA technology?
Answer:
(a) Isolation of genetic material DNA.
(b) cutting of DNA at specific locations,
(c) Gel electrophoresis.
(d) Amplification of gene using PCR.
(e) Insertion of recombinant DNA into the host.
(f) Obtaining the foreign gene product,
(g) Down stream processing.

Question 43.
What is polymerase chain reaction?
Answer:
It is a technique in which a gene of choice is amplified into many .copies using primers and DNA polymerase enzyme.

Question 44.
Define Downstream processing or Write a note on downstream processing.
Answer:
It is the purification of useful products after biosynthetic stages from natural sources i.e., separation and purification of Biosynthetic products.

Downstream processing is the purification of useful products after biosynthetic stages from natural sources,
i. e., separation and purification of Biosynthetic products. “Various processes used for the recovery of useful products after biosynthetic stage”. This includes separation and purification and the product has to be formulated with preservatives. Such formulation has to undergo through clinical trials (drugs) and Quality control testing for each product is required. The downstream processing and quality control testing vary from product to product.

→ Insertion of Recombinant DNA, after making them competent. Once it is received, it becomes genetically . modified cell.
Ex: Transformed E.coli with Rec-DNA resistant to Ampicillin, will grow on ampicillin containing media, where non transformed will not grow.

→ Obtaining The Foreign Gene Product:
Recombinant plasmids under proper conditions gels expressed and synthesise desired proteins and these proteins are separated and purified by following technique i.e., ‘protein encoding gene is expressed in a heterologous host’ which forms Recombinant protein.

→ Downstream Processing: Various processes used for the recovery of useful products after biosynthetic stage”. This includes separation and pu-rification and the product has to be formulated with preservatives. Such formulation has to undergo thorough clinical trials (drugs) and Quality control testing for each product is required. The downstream processing and quality control testing vary from product to product.

2nd PUC Biology Important Questions with Answers

Karnataka 2nd PUC Biology Important Questions Chapter 10 Microbes in Human Welfare

Question 1.
Write a note on microbes used in household products? or Explain the role of Microbes in Household products?
Answer:
(a) Curd: One of the examples of fermenting activities of microorganisms. Ans; (1-lj)
(b) Lactic Acid Bacteria (LAB) Ex: L. lactis, L, acidophilus, L. bulgaricus etc. .
MECHANISM

Question 2.
Explain the mechanism of milk turning into curd by LAB?
Answer:
Conversion of lactose of milk into curd. LAB produce acids that coagulate and partially digest milk proteins.
A small amount of curd added to milk as inoculum or starter at suitable temp (50 – 40° c) for 6 to 8 hrs.

Question 3.
Give benefits of curd?
Answer:
Benefits: Improves nutritional quality by increasing Vit. B₁₂. They check disease-causing microbes.

Question 4.
Name the vitamin present in curd?
Answer:
Vitamin B₁₂.

Question 5.
In which food would you fined LAB?
Answer:
Curd

Question 6.
Give any 2 examples, that microbes evolve gases during metabolism?
Answer:
1. Dosa and Idli – Bacterial fermentation of rice and black gram leads to CO₂ evolution, which causes doughing of raw material. Atmospheric bacteria like Leuconostoc mesenteroides, Pseudococcus cerevisiae, Streptococcus faecalis etc. enhance this action.

2. Wheat flour and water is mixed with Baker’s yeast saccharomyces cerevisiae liberate CO₂ which results in Dough, which makes the bread soft and porous.

Question 7.
Name the microbe used in production of bread?
Answer:
Saccharomyces ceresvisiae (yeast)

Question 8.
What is Toddy?
Answer:
A traditional drinks prepared by fermenting sap, obtained from toddy palm in florescence (spadix) is tapped for toddy. [Note: Neera obtain from Coconut plant is a refreshing drink, when heated produce palmsugar and jaggery],

Question 9.
Name the source of Toddy?
Answer:
Toddy (Phoenix dactylifera).
[Note: Fermented fish, soyabean, Bamboo shoots are used as food].
CHEESE: Oldest food items, prepared by activities of microbes. Different varieties of cheese are known for their texture, flavor, taste etc.
Ex: (a) Swiss Cheese – with special flavour and large holes.

Question 10.
Write the role of microbe’s in house hold food products.
Answer:
(a) CURD: One of the examples of fermenting activities of microorganisms.
Lactic Acid Bacteria (LAB)
Ex: L. lactis, L. acidophilus, L, bulgaricus etc.
Benefits: Improves nutritional quality by increasing Vit. B₁₂.

(b) They check disease-causing microbes. Vitamin B₁₂

1. Swiss cheese by propionibacterium
2. Roquefort cheese

(c) DOUGH for making foods:
Ex: Idli, Dosa, Bread, Jalebi Prepared by the fermentation process.
Saccharomyces cerevisiae (yeast).

(d) Toddy is a fermented drink from palms.

Question 11.
Why large holes are seen in Swiss cheese? or Mention the bacteria responsible for the large holes seen in Swiss Cheese.
Answer:
Large holes are due to large amount of CO₂ released by the thermophilic bacteria Propionibacterium shamanic.

Question 12.
Which Species of penicillium produces Roquefort cheese?
Answer:
(b) Roquefort Cheese: Prepared by sheep’s milk and is ripened by growing a fungus Penicillium Roquefort. [Note: This cheese has- Green blue mottling colours with particular flavour,.These living microorganisms are probiotics, which influence intestinal microflora, which cure intestinal disorders]

Question 13.
Explain the role of microbes as industrial products?
Answer:
A number of powerful industries are* based on beneficial activities of microbes. They aim towards growing microbes in very large scales in a specialised vessel called Fermentors or Bioreactors.

Examples: 1. Fermented beverages: prepared by using yeast – Saccharomyces cervisiae.
Bread making, Alcoholic drinks, Undistilled Wine, Beer, Whisky, Brandy, Rum and distilled hard liquors

Question 14.
Give one appliction of Brewer’s yeast?
Answer:
Brewer’s yeast, Saccharomyes cerevisiae is used for Fermenting purpose using malted cereals and fruit juices to produce ethanol and Grape-wine.

Question 15.
What are Antibiotics, give one example?
Answer:
These are the chemical substances which are produced by some microbes and can kill or retard the growth of other micro organisms (disease-causing) Ex: Penicillin

Question 16.
How was Penicillin discovered?
Answer:
Pencillin was discovered by Alexander flemming. He experimented on Staphylococcus bacteria. Which could not grow on unwashed culture plates, he concluded that it was due to chemical produced by fungi Penicillium notatum.

Question 17.
Name two scientists who experimented the role of penicillin as an antibiotic?
Answer:
Ernst chain and Howard Florey – Experimented using this antibiotic in world war II to treat American soldiers. They got Nobel prize 1945.
[Note: Most of the antibiotics are from 3 groups of microorganisms.

1. Eubacteria – Bacillus.
2. Ramified bacteria – Streptomyces
3. Fungi – Pencil, Aspergillus, Cephalosporium.

Question 18.
Name the source of Penicillin?
Answer:
Penicillium notatum Chemicals, Enzymes and other Bioactive molecules

Question 19.
Name the microorganism which produces butyric acid.
Answer:
Clostridium butylicum.

Question 20.
Write a note on microbes application as chemical, enzymes and bioactive molecules?
OR
Mention any 5 microbes and their commercial or industrial products.
Answer:
Microbes are also used for the commercial and industrial production of chemicals like organic acids, alcohols, and enzymes.
Acid producers are:

• Aspergillus niger (fungus) → Citric Acid.
• Acetobacter aceti (bacterium) → Acetic acid.
• Clostridium bretylium → Butyric acid.
• Lactobacillus → Lactic acid.

Question 21.
Name the sources of Acetic acid and citric acid?
Answer:
Acetobacter aceti and Aspergillus niger.

Question 22.
Name an organism producing pectinase. Mention the use of pectinase?
Answer:
Aspergillus niger produces Pectinases and Proteases → Used for clarification of bottled fruit juices to clarify.

Question 23.
Name any two industrially important enzymes and their uses?
Answer:

1. Invertase → Production of ethanol.
2. Pectinases → Used for clarification of bottled fruit juices.

Question 24.
Name the enzyme and its source used in detergent?
Answer:
Candida albicans (Fungi) Produces enzyme → Lipases → used in detergent are helpful in removing oily stains

Question 25.
Name the source Clot bluster and its action?
Answer:
Streptococcus produces the enzyme is Streptakinase → modified genetically and used as ‘Clot bluster’ for removing clots from blood vessels of patients of myocardial infarction leading to a heart attack.

Question 26.
Name the source of cyclosporin A? Mention the use of cyclosporin-A.
Answer:
Cyclosporin: A bioactive molecule, which is produced by fungus Trichoderma polysporum., acts as an immunosuppressive agent in organ-transplant patients.

Question 27.
Name the bioactive molecule used in organ transplantation. Who provided an experimental proof for the chemical evolution of life?
Answer:
Cyclosporin A [Stanley Miller and Harold Urey].

Question 28.
Which Bioactive moecule is used as an immunosuppressive agent?
Answer:
Cyclosporin A

Question 29.
Name the fungus that produce statin? Explain its function.
Answer:
2. Monascus purpereus (Yeast) – Statin → acts as blood Cholesterol lowering agent. Inhibits enzyme synthesis, which is responsible for synthesis of cholesterol.

Question 30.
Mention the use of Statin?
Answer:
Blood cholesterol-lowering agent.

Question 31.
Name the fungus that produces cyclosporin A?
Answer:
Trichoderma polysporum.

Question 32.
Define Sewage?
Answer:
It is municipal wastewater containing domestic water born wastes including human and animal excreta etc.
[This can not be discharged into natural water bodies like rivers and streams, so it is treated in sewage treatment plants (STP) to make it less polluting by using heterotrophic microbes.]

Question 33.
Expand STP?
Answer:
Sewage treatment plant.

Question 34.
Mention two stages of STP?
Answer:
Two stages:

1. Primary treatment
2. Secondary treatment.

Question 35.
Explain steps involved in sewage treatment? or Explain different stages involved in Sewage treatment.
Answer:
1. Primary Treatment: It is a physical removal of large and small particle from the sewage through filtration and sedimentation. Initially floating debris is removed by sequential filtration. Later-The grit (soil and small pebbles) removed by sedimentation. This concentrated solid material that settles down forms the PRIMARY SLUDGE, supematent forms the Effluent. Effluent is taken for secondary treatment.

2. Secondary treatment/Biological treatment:
The primary effluent is passed into large aeration tanks, and air is pumped into it to make it aerobic, which allows vigorous growth of useful aerobic microbes into “FLOCS”

“Masses of bacteria associated with fungal filaments to form mesh-like structures”.
While growing thege microbes consume the major part of the organic matter in the effluent (by oxidation), so BOD is reduced. After BOD reduction, the effluent is passed into a sedimentation tank, where the microbial floes are allowed to settle down, this settled material ‘Activated Sludge’, a small part of it is pumped back into aeration tank to serve as the Inoculum.

The remaining major part of the sludge is pumped into large tanks called Anaerobic Sludge digester, here
other anaerobic microorganisms start digesting bacteria and fungi in the sludge. During this digestion bacteria produce a mixture of gases such as Methane, H2S, and C02 which are highly inflammable can be used as [Biogas].

[Note: The number of STP is not enough in our country to treat large sewage quantities, so the untreated sewage is often discharged directly into rivers leading to pollution and increase in water bom diseases. The ministry of Environment, Forest has initiated GANGA ACTION PLAN and YAMUNA ACTION PLAN to save these major rivers of our country form pollution, so that only treated sewage may be discharged into the rivers.]

Question 36.
Define BOD?
Answer:
BOD → Biochemical Oxygen Demand → It is the amount of the oxygen, that would be consumed if all the organic matter in one litre of water, were oxidised by bacteria. [BOD is a measure of the organic matter present in the water, greater BOD, more is its polluting potential.]

Question 37.
What is Activated Sludge?
Answer:
After reduction of BOD of effluent in Sewage treatment plant, it is passed into sedimentation tank, where the microbial floes are allowed to settle down, this settled material is Activated Sludge.

Question 38.
BOD is an index of water pollution? Comment.
Answer:
The BOD test measures the rate of uptake of oxygen by micro organisms in a sample of water and thus indirectly BOD is a measure of the organic matter present in the water. The greater the BOD value of wastewater, more the pollution.

Question 39.
What are FLOCS? Microbial floes?
Answer:
Masses of bacteria associated with fungal elements to form mesh like structure.

Question 40.
Disposal of sewage into water without proper treatment may cause of serious diseases? Give reason.
Answer:
Sewage contains large amounts of organic matter and microbes, many of which are pathogenic.

Question 41.
Define Biogas. Mention the components of biogas?
Answer:
Biogas is a mixture of gases (65% Methane, 30% CO₂, and the remaining 5% includes H₂, N₂, O₁, and H₁S) produced from degradable organic matter by the activity of ‘Anaerobic bacteria’, which may be used as fuel.

Question 42.
What are Methanogens? Give one example of methanogenic bacteria?
Answer:
Certain anaerobic bacteria which grow anaerobically on cellulosic material produces- Methane, CO, and Hr They are known as Methanogens, Ex: Methanobacterium ruminated.

Question 43.
Mention the role in methanobacterium in cattles?
Answer:
Methanobacterium present in rumen of cattle, break down cellulosic material anaerobically which is present in the food and play important role in the nutrition of cattle.

Question 44.
What is Gobar gas?
Answer:
The excreta of cattle i.e, dung, commonly called gobar is rich in methanobacterium, so this dung can be used for generation of biogas known as gobar gas.

Question 45.
Name the institutes which helped in the development of bio fuel technologies in India?
Answer:
This technology was developed by efforts of Indian Agricultural Research Institute (IARI) and Khadi and Village industries commission (KVIC).

Question 46.
Explain the Mechanism of .Working of Biogas plant?
Answer:
The biogas plant has a concrete tank (10-15 ft deep) in which biowastes and slurry of dung is collected.
The tank has a floating cover which rises on production of gas in the tank, due to microbial activity.
After filling slurry biogas tank is covered by the floating lid. Methanobacterium in the dung act on the biowastes to produce biogas. The biogas plant has an outlet, which is connected to a pipe to supply biogas to nearby houses.
The spent slurry (sludge) is removed through another outlet and may be used as fertilizer.

Question 47.
Draw a neat labelled diagram of Biogas plant?
OR
Describe the parts of a biogas plant with a labelled diagram?
Answer:
Biogas plant consist of vessel in which dung and water are added it is connected to a dome shaped vessel in which there is another vessel placed which contains methane and C02 gas this is termed as gas holder on the upper side there is a pipe through which the gas escapes. Gas holder is connected to a vessel in which the sludge is placed. The biogas plant is used in rural areas for cooking purpose.

Question 48.
What is Biocontrol?
Answer:
Biocontrol: Use of biological methods for controlling plant diseases and pests.

Question 49.
What are the harmful effects of insecticides and pesticides?
Answer:

• Chemical insecticides and pesticides are extremely harmful to human beings and animals.
• Pollute Environment and plants. Pollute soil through chemical weedicides.
• Create ecological imbalance by disturbing the food chain/food web by the eradication of field fauna and flora (pests).

Question 50.
Explain why biocontrol is considered a holistic approach?
Answer:
Reduce our dependence on toxic chemical pesticides. Familiarity with various life forms inhabiting the field.
Knowledge about the life cycles, patterns of feeding habitat of predators and pests, which help to develop appropriate means to biocontrol.

Question 51.
Explain the role of microbes used as Biocontrol agents with examples?
OR
Name the controlling agents to control aphids and mosquitoes?
Answer:

1. Dragonflies and Ladybirds are used to get rid of aphids and mosquitoes.
2. Bacillus thuringiensis – control caterpillars of butterfly.
   Available in dried powdered form of spores, which is mixed with water and sprayed on plants, which kill caterpillars and leave other insects unharmed.
   Bt toxin genes have been introduced into plants to provide resistance to pests, ex: Bt cotton.
3. Trichoderma (fungus) – present in the root ecosystem is effective on plant pathogens.

Question 52.
Write a note on Baculovirus?
Answer:
Baculoviruses of genus Nucleopolyhedrovirus – attack insects and other arthropods. It is Excellent species-specific narrow-spectrum insecticide. They have negative impacts on plants, mammals, birds, fishes and other non-target insects.
Desirable when beneficial insects are conserved and help in Integrated Pest Management (IPM) programme or when an ecologically sensitive area is treated.

Question 53.
What are Biofertilizers?
Answer:
Biofertilizers – Organisms that enrich the nutrient quality of the soil.
[Need – Chemical fertilizers are toxic and harmful and pollute the soil and environment.
Approach – Organic farming i.e. usage of bio fertilisers.

Examples: Main sources
(a) Bacteria
(b) Fungi
(c) Cyanobacteria],

Question 54.
Describe the role of microbes as bioferfilizers? or Explain the role of bacteria, Cyanobacteria and of fungi in the enrichment of quality of soil.
Answer:

1. Dragonflies and Ladybirds are used to get rid of aphids and mosquitoes.
2. Bacillus thuringiensis – control caterpillars of butterfly. Available in dried powdered form of spores, which is mixed with water and sprayed on plants, which kill caterpillars and leave other insects unharmed. Bt toxin genes have been introduced into plants to provide resistance to pests, ex: Bt cotton.
3. Trichoderma (fungus) – present in root ecosystem is effective on plant pathogens.
4. Baculoviruses of genus Nucleopolyhedrovirus – attack insects and other arthropods. It is Excellent species specific narrow-spectrum insecticides. They have negative impacts on plants, mammals, birds, fishes and other non target insects.
   Desirable when beneficial insects are conserved and help in Integrated Pest Management (IPM) programme or when an ecologically sensitive area is treated.
5. Biofertilizers – Organisms that enrich the nutrient quality of the soil.
   [Need – Chemical fertilizers are toxic and harmful and pollute the soil and environment.
   Approach – Organic farming i.e. usage of bio fertilizers. Examples: Main sources (a) Bacteria (b) Fungi (c) Cyanobacteria],

Bacteria:
Rhizobium – Fix atmospheric nitrogen, in leguminous plants. Free-living nitrogen-fixing bacteria – Azospirillum and Azotobacter, enrich the nitrogen content of the soil.

Question 55.
Discuss the role of fungi as bio fertilizers?
Answer:
Fungi form symbiotic association with the roots of higher plants called Mycorrhiza.
Ex: Glomus. The fungal hyphae absorbs phosphorus from soil and passes into the plant.
Benefits of Mycorrhiza:
(a) resistance to root bom pathogens
(b) tolerance to salinity and drought
(c) Overall increase in plant growth and development.

Question 56.
How cyanobacteria are useful to plants?
Answer:
Cyanobacteria are autotrophic microbes, widely distributed (aquatic and terrestrial) can fix atmospheric nitrogen fixation. Eg. Anabaena, Nostoc, Oscillatoria etc.

They serve as bio fertilizers in paddy fields. Blue-green Algae add organic matter and increase the fertility of the soil. Regular use of biofertilizers from the market to replenish soil nutrients and reduce dependence on chemical fertilizers.

Question 57.
Give an account of microbes used as Biofertilizers.
Answer:
1. Rhizobium symbiotic bacteria – Fix atmospheric nitrogen, in leguminous plants. Free-living nitrogen-fixing bacteria – Azospiriullum and Azotobacter, enrich the nitrogen content of the soil.

2. Fungi: Fungi form a symbiotic association with the roots of higher plants called Mycorrhiza. Ex: Glomus.

• The fungal hyphae absorb phosphorus from soil and pass into the plant.
• They serve as biofertilizers in paddy fields.
• Blue-green Algae add organic matter and increase fertility of the soil.
• Regular use of biofertilizers from the market to replenish soil nutrients and reduce dependence on chemical fertilizers.

Question 58.
Write the role of microbe’s in household food products.
Answer:
(a) CURD: One of the examples of fermenting activities of microorganisms.
Lactic Acid Bacteria (LAB).
Ex: L. lactis, L. acidophilus, L. bulgaricus etc.
Benefits: Improves nutritional quality by increasing Vit B₁₂

(b) They check disease-causing microbes. Vitamin B₁₂.

1. Swiss cheese by propionibacterium
2. Roquefort cheese

(c) Dough for making foods: Ex: Idli, Dosa, Bread, Jalebi prepared by the fermentation process, Saccharomyces cerevisiae (yeast).

(d) Toddy is a fermented drink from palms.

→ Microbes: Microscopic organisms which are not visible with naked eyes and viewed under microscope.
Ex: Bacteria, Viruses, Yeasts etc.

• They are omnipresent.
• Adaptability to the entire biosphere
• They can be grown and multiplied on specific ‘Culture media’ consisting of various nutrients and hormones. Both useful and harmful microbes.
• The close relationship of man and microbes is as early as 5000 B.C. in making Curd, Bread, Wine, Vinegar etc.

2nd PUC Biology Important Questions with Answers