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Karnataka 1st PUC Biology Previous Year Question Paper March 2015 (South)
Time: 3.15 Hours
Max Marks: 70
- The question paper consists of four parts A, B, C, and D.
- All the parts are compulsory.
- Draw diagrams wherever necessary. Unlabelled diagrams or illustrations do not attract any marks.
Part – A
Answer the following questions in one word / one sentence each: ( 10 × 1 = 10 )
What is a taxon?
Classification unit in Linnae& hierarchy ¡s called taxon.
Write the binomial name of the plant mango.
What is an actinomorphic flower?
A flower can be divided into two equal radial halves in any radial plane passing through the center.
Define a cell.
The cell is the fundamental, structural and functional unit of all living organisms.
Name the proteins that are involved in the transport of molecules across the membrane.
Define solute potential.
Decrease in water potential due to dissolution of solute into the solvent.
Which is the most abundant plant pigment present in the world?
What is chlorosis?
Yellowing of leaf due to lack of chlorophyll pigment.
Name the cells present in the mucosal epithelium of the small intestine that secretes mucus.
Name the hormone that is secreted by the pineal gland.
Answer any FIVE of the following questions in 3-5 sentences each, wherever applicable. (5 × 2 = 10)
Write the four universal rules of binomial nomenclature.
- Scientific names are, generally, written in Latin or derived from Latin, irrespective of their origin.
- The scientific names are written in italics or underlined. The first word denotes the name of the genus, and the second word denotes the species.
- The generic name starts with a capital letter, while the specific name starts with a small letter.
- The name of the author is written in an abbreviated form after the specific name e.g. Mangifera Indica Linn.-indicates that this species was first described by Linnaeus.
- The name should be short, precise, and easy to pronounce.
Name two symbiotic associations of Lichens.
Algae and Fungi.
What are diploblastic animals? Name the phylum that exhibits diploblastic condition.
Animals whose body wall is made up of two germ layers are called diploblastic animals. eg: Hydra.
Differentiate between the open and closed types of vascular bundles.
Open type of vascular bundles:
If the cambium is present in between the xylem and phloem, then the vascular bundle is said to be open type. it is closed for secondary growth.
Closed type of vascular bundles:
If the cambium is absent in between the xylem and phloem, then the vascular bundle is said to be closed type.
Name four main types of tissues present in animals.
- Epithelial tissue
- Connective tissue
- Muscular tissue
- Neutral tissue
Mention four types of chromosomes based on the position of the centromere.
I. Classification of chromosomes based on the number of centromeres:
(a) Acentric chromosome: It is a chromosome without centromere.
(b) Monocentric chromosome: Here there is one centromere to hold the chromatids together.
(c) Iiiceiitric chromosome: It is the presence of two centromeres in a chromosome.
(d) Polycentric chromosome: It is more than three centromeres in a chromosome.
II. Classification of chromosomes based on the position of centromere:
(a) Metacentric type: Here the centromere is exactly at the center of two chromatids. it looks V-shaped during anaphase.
(b) Sub metacentric type: Here the entrance is eccentric in position so that one of the chromatids is long and the other is shorter. It looks L – shaped during anaphase.
(c) Acrocentric type: Here the centromere is almost towards one end of the chromatid to form a very long arm and another very short arm. It looks hook-shaped during anaphase.
(d) Telocentric type: Here the centromere is towards one end of the chromatid such that one chromatid is only present. It looks rod-shaped during anaphase.
III. Classification of chromosomes based on their functions:
(a) Autosomes[AA]: They are also called somatic chromosomes that control body characteristics.
(b) Allosomes IX or VI: They are also called sex chromosomes that determine the gender of an individual.
Functions of chromosomes:
- Chromosomes are very important in the higher animals for the phenomenon of sex determination.
- Chromosomes play an active role in the metabolic process of a cell.
- They carry the heredity information from parents to offspring ¡n the form of genes.
Give the meaning of the terms (a) Photoperiodism (b) Vernalisation
Plants, in order to flower, require a particular day length or light period called photoperiod, and the response of the plants to photoperiod in terms of flowering is called photoperiodism.
Photoperiodism was first studied by W.W. Garner, and HA. Allard.
Based on their photoperiodic responses, plants are classified into the following groups:
- Long Day Plants: These flower in photoperiod more than critical day length. eg: Wheat, oats, etc.
- Short Day Plants: These flower in photoperiod less than critical day length. e.g: Tobacco, Chrysanthemums, etc.
- Day Neutral Plants: These are the plants that are not influenced by the dûration of light for their flowering. e.g: Tomato, cucumbër, cotton, etc.
Besides correct photoperiod, somç plants require low-temperature treatment for flowering. This treatment is known as vernalization.
Vernalization prevents precocious reproductive development late in the growing season and enables the plant to have sufficient time to reach maturity.
Certain food plants like wheat, barley, and rye have two varieties called,
- Spring variety, and
- Winter variety.
The spring variety is planted in spring, and it completes the lifecycle before the growing season.
The winter variety ¡s normally planted in autumn or spring and is harvested by mid-summer.
Name two kinds of contractile proteins present in myofibrils.
Answer any FIVE of the following questions in 40-80 words each, wherever applicable: (5 × 3 = 15)
Sketch and label the structure of the chloroplast.
Electron microscopic structure of the chloroplast
How would you identify the following stages of meiosis-I?
(a) Leptotene (b) Zygotene (c) Pachytene
(a) Leptotene: Chromosomes are clearly visible as they undergo condensation.
(b) Zygotene: Two identical chromosomes are pairing called synapsis.
(c) Pachytene: Crossing over occurs between non-sister chromatids of homologous chromosomes.
What are proteins? Name the most abundant protein present in plants and animals.
Proteins are polypeptides made up of a chain of amino acids.
Abundant proteins found in
Plants – RUBISCO / RUBP Carboxylase
Animals – Collagen
Explain three phases of the sigmoid curve.
The curve obtained when the growth in size or weight or on entire pLant or its individual parts is plotted against time is called the growth curve. It is always ‘S’ or sigmoid in shape. it shows three distinct phases namely.
- Lag phase.
- Log phase.
- Steady phase.
1. Lag phase: This is the initial stage where the growth rate is very slow. But it gradually increases with time.
2. Log phase: In this phase, the rate of growth is very rapid. The plant shows a high rate of growth and reaches maximum height. Hence this phase is called the exponential phase or grand period of growth.
3. Steady phase or stationary phase: This is the last phase in which plants show no growth. Therefore the growth curve becomes almost horizontal.
Give the meaning of the terms (a) Antiport (b) Osmosis (c) Guttation
(a) Antiport: Movement of molecules across the membrane in both directions.
(b) Osmosis: It is a special type of diffusion in which only the solvent or water molecules move from a region of their higher concentration to a region of their lower concentration through a semi-permeable membrane.
(c) Guttation: The loss of water in liquid form through specialized structures called water stomata or hydathodes is called guttation.
Describe briefly the digestion of three types of food by the enzymes of the pancreas.
Name the three layers of cranial meninges present between skull and brain.
(a) Outer Dura mater.
(b) lyiiddle Arachnoidmater
(c) Inner Pia mater
(a) Mention the types of antigen and antibody present in different blood groups of man.
(b) What is uremia?
Uraemia is a condition, where urea gets accumulated in the blood due to the failure of nephrons in the kidney.
Part-D (Section – I).
I. Answer any FOUR of the following questions in 200-250 words each. (4 × 5 = 20)
Write five general characteristic features of bryophytes.
- They are non-vascular plants, exhibiting amphibious habitats.
- The gametophytic phase of the life cycle is representeð by multicellular, haploid thallus, which is called gametophyte.
- Gametophytic plant body bearing male and female sex organs, represents the dominant phase of life cycle unlike in higher plants.
- The gametophyte is autotrophic and independent in nature.
- The gametophyte produces sex organs, the antheridia and the archegonia which are multicellular.
Antheridia may be embedded within the thallus or may be specifically located at the tips of the gametophyte. It produces biciliate curved antherozoids.
Archegonia is a flask-like structure, it bears a basal bulbous vendor and a narrow, hallow structure at it is summit called the neck. Within the venter, the female gamete or egg is situated along with a venter canal cell. The neck shows neck cells, neck canal cells, and cover cells.
Sketch and label the alimentary canal of the cockroach.
Classify enzymes into five types based on the type of reactions they catalyze.
Classification of enzymes:
- Oxidoreductases: Act on many chemical groupings to add or remove hydrogen atoms.
- Transferases: Transfer functional groups between donor and acceptor molecules. Kinases are specialized transferases that regulate metabolism by transferring phosphate from ATP to other molecules. ,
- Hydrolases: Add water across a bond, hydrolyzing it.
- Lyases: Add water, ammonia, or carbon dioxide across double bonds, or remove these elements to produce double bonds.
- Isomerases: Carry out many kinds of isomerization: L to D isomerizations. Mutase reactions (shifts of chemical groups) and others.
- Ligases: Catalyze reactions in which t chemical groups are joined (or ligated) with the use of energy from ATP.
Explain the major events of the photochemical phase of photosynthesis.
It is a totally light-dependent process.
(a) Photoexcitation of chlorophyll.
(b) Photo phosphorylation – cyclic and noncyclic.
(c) Photolysis of water (photoionization of water).
(a) Photoexcitation of chlorophyll: Chlorophyll absorbs light energy as photons. Photoexcited chlorophyll ejects energized electrons, and becomes positively charged, and remains unstable. It regains stability only when its lost electrons are replaced.
(b) Photo phosphorylation:
The extra energy of ejected electrons during photoexcitation is used for phosphorylation of ADP into ATP1-Ìence it is called photophosphorylation. It is of two types namely,
(a) Cyclic Photophosphorylation
(b) Non-cyclic Photophosphorylation.
(a) Cyclic Photophosphorylation: It is a cyclic path of electrons expelled from chlorophyll through a series of substrates that are arranged in a suitable oxidation-reduction potential. The energy in the electrons is used for the phosphorylation of ADP to ATP.
In PS I the absorbed photons of light excite chlorophyll-a 700 to eject energized electrons on makes it positively charged and unstable. Electrons pass through the sequence → FRS → FD → Cyt b6 → Cytf → PC and generate ATP at two places. Finally, an electron from PC returns to chi-a restoring its stability.
(b) Non-cyclic Photo phosphorylation:
1. It is the noncyclic path of electrons from PS Il, and PS Ito release ATP and NADPH2, with the help of protons and electrons from photolysis of water
2. In PS I the absorbed photons of light excite chlorophyll-a 100 to eject energized electrons which pass through FRS, FD, and finally get locked up with NADP which becomes negatively charged, and partially reduced, while PSI becomes positively charged and unstable.
3. At the same time in PS II, the absorbed photons of light excite chlorophyll-a 680 to eject energized electrons which pass through in sequence, pheophytin, PQ, to b6, cytf, plastocyanin, and generate ATP. The electrons finally join P.S Ito replace its lost electrons and restore its stability. Now P.S Il becomes positively charged, and unstable. Meanwhile, electrons of photolyzed water join with PS Jito to replace its lost electrons and restore its stability. Protons join with the already ionized NADP and complete its reduction to NADPH2.
Write the schematic representation of glycolysis.
It occurs ¡n the cytoplasm of the cell.
It is an enzymatic reaction, thus temperature sensitive.
It ¡s a common reaction for both aerobic and anaerobic respiration.
Describe the mechanism of breathing.
It is a process of intake of oxygen and leaving out carbon dioxide from the lungs. The mechanism of breathing involves.
1. Inspiration (Inhalation): It is the process of drawing air into the lungs from the outside atmosphere (intake of air). During this process, muscles of the diaphragm contract, which increases the length of the thorax. In meanwhile intercostal muscles also contract, pulling the ribs outward. This phenomenon increases the width of the thorax, resulting in the expansion of the lungs. As a consequence pulmonary pressure falls. So oxygen-rich air rushes into the lungs and fills alveoli.
2. Exchange of gases: The alveoli are closely surrounded by a thin wallet! epithelium, having a capillary network. The oxygen is under high pressure in alveoli, because of its higher concentration. Similarly, carbon dioxide concentration and pressure will be more in the capillaries containing impure blood.
So, the exchange occurs by diffusion through the capillary walls. The oxygen is drawn into the blood, and carbon dioxide is pushed into the alveoli.
3. Expiration (exhalation): lt is the process of throwing out carbon dioxide from the lungs to the outside. During this process, muscles of the diaphragm and intercostal muscles relax causing the collapse of the rib cage. This decreases the volume of the thorax and lungs.
As a consequence pulmonary pressure increases. So, the carbon dioxide-rich air of the alveoli is drawn out through the respiratory passage.
Section – II
II. Answer any THREE of the following questions in 200-250 words each, wherever applicable. (5 × 3 = 15)
(a) Assign the following animals to their respective phylum. (3M)
(i) Comb jellies
(b) Describe four important features of Aves.
- Presence of feathers.
- Presence of pneumatic bones: Pneumatic bones are long hollow bones with air cavities.
- Forelimbs are modified into wings to help in flight.
- Hind limbs generally have scales helping them to clasp the prey in-flight or a tree branch.
- Excretion of uric acid and feces is through a single opening, and excretion uses a very little amount of water, to reduce body weight.
- An aerodynamically built body helps in flying (by reducing friction).
What is aestivation? Mention any four types with one example for each.
The mode of arrangement of sepals, petals, or even tepals in a flower bud is called aestivation. The different kinds of aestivation are as follows:
1. Valvate aestivation: When sepals, petals, or tepals are not overlapping.
2. Imbricate aestivation: When out of the total number of sepals. petals or tepals, one is completely out, one is completely in and the rest are in and out.
3. Descending imbricate aestivation: When the standard petals are large and overlap the two wing petals, which in turn overlap the keel petals. It is technically known as vexillary aestivation.
Note: It is characteristic of the members of the subfamily Papilionoideae (Papilionaceae). e.g: Pea, Bean, Indigofera, Tephrosia, etc.
4. Ascending imbricate aestivation: When the small standard petal is completely ¡n and is overlapped by the lateral wing petals which in turn are overlapped by the keel petals.
Note: It is characteristic of sub-family Caesalpinioideae (Caesalpinae).
eg: Caesalpinia puicherhima, Delonix regia, etc.
With the schematic representation explain Calvin Cycle.
It occurs in the grana of the chloroplast.
It utilizes the assimilatory powers i.e., ATP and NADPH2 produced in light reaction.
- Carbon dioxide fixation
- Phosphorylation and reduction.
- Regeneration and RUMP
- Glucose formation.
Note: To complete a Calvin cycle, 18 ATPs and 12 NADPH2 molecules are required.
Sketch and label the structure of the nephron.
What is ECG? Explain it with the graphical presentation of a standard ECG
ECG has 5 waves or deflections which are conventionally designated as PQRST. The five waves have a horizontal part in the beginning as well as inside. It is called isopotential or baseline. PR and T waves lie above the horizontal line. They are called positive waves. Q and S waves lie below the horizontal line and are therefore called negative waves. P represents the development of action potential at the sinoatrial node and the spread of impulse throughout the atria.
The atrial muscles become depolarized. After a fraction of a second, the next complex of QRS begins with a small downward or negative reflection of Q. QRS represents depolarization of atrial muscles and depolarization of ventricular muscles. Its different components are PQ, QR, and RS. PQ indicates contraction of atria.
QR provides information about the spread of cardiac impulses from the SA node to the AV node. RS gives information about the spread of impulse from the AV node to Purkinje fibers and ventricular depolarization. It initiates the contraction of the ventricles. The ventricular contraction continues during the ST part. It is followed by the relaxation of ventricles and the development of the repolarisation wave.