Board Question Paper: July 2023
BIOLOGY
Time: 3 Hrs. Max. Marks: 70
- The question paper is divided into four sections.
- Section A: Q. No. 1 contains Ten multiple choice type of questions carrying one mark each.
- For each multiple choice type of question, it is mandatory to write the correct answer along with its alphabet, e.g., (A) ……. / (B) ……. / (C) ……. / (D) ……. etc. No mark/s shall be given if ONLY the correct answer or alphabet of the correct answer is written.
- In case of MCQ, evaluation will be done for the first attempt only.
- Q. No. 2 Contains Eight very short answer type of questions carrying one mark each.
- Section B: Q. No. 3 to 14 are short answer type of questions carrying two marks each. (Attempt any Eight)
- Section C: Q. No. 15 to 26 are short answer type of questions carrying three marks each. (Attempt any Eight)
- Section D: Q. No. 27 to 31 are long answer type of questions carrying four marks each. (Attempt any Three)
- Begin the answer of each section on a new page.
Q.1. Select the correct alternatives and write the answers: [10]
i. If members of two populations have difference in the structure of reproductive organs, then this type of isolation is called _______.
ii. The primary precursor of Indole-3-Acetic acid is _______.
iii. If only one DNA molecule is subjected to PCR and the time required for each cycle is three minutes, then after five cycles, how many DNA molecules are obtained?
Explanation: Number of DNA molecules = \(2^n\), where \(n\) is the number of cycles. \(2^5 = 32\).
iv. The specific gravity of CSF is _______.
v. Cardiac output of a person is 5400 ml and heart rate 72 per min. What will be his stroke volume?
Explanation: Stroke Volume (SV) = Cardiac Output (CO) / Heart Rate (HR) = 5400 / 72 = 75 ml.
vi. Detritus food chain starts from _______.
vii. Plants absorb _______ water.
viii. The organisms having tolerance for wide range of salinity are called _______.
ix. Hisardale is a new breed of sheep developed by crossing _______.
x. Perforins are secreted by _______.
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Q.2. Answer the following questions: [8]
i. Mention the chromosome number having the mutated gene for β-Thalassemia.
ii. Which organ produces calcitriol?
iii. If the megaspore mother cell has 26 chromosomes, what will be the total number of chromosomes in endosperm of the same plant?
Endosperm is triploid (3n).
Total chromosomes = 3 × 13 = 39 chromosomes.
iv. Define the term − Facilitated diffusion.
v. Give reason − Energy pyramid is always upright.
vi. What will be the base sequence on the template strand of DNA, which codes for methionine?
vii. Deficiency of which element causes Brown heart disease in plants?
viii. Where are the cells of Rauber situated in the blastocyst of human embryo?
Attempt any EIGHT of the following questions: [16]
Q.3. i. Give one example each of:
a. Autosomal dominant traits
b. Autosomal recessive traits
b. Autosomal recessive traits: Phenylketonuria (PKU) / Cystic fibrosis / Sickle cell anaemia.
ii. If a carrier woman marries a colorblind man, what will be the phenotype of their progeny? Show in the form of a chart.
Gametes: (\(X^C\), \(X^c\)) and (\(X^c\), \(Y\))
Progeny Chart:
| Gametes | \(X^c\) | \(Y\) |
|---|---|---|
| \(X^C\) | \(X^C X^c\) (Carrier Daughter - Normal Vision) | \(X^C Y\) (Normal Son) |
| \(X^c\) | \(X^c X^c\) (Colorblind Daughter) | \(X^c Y\) (Colorblind Son) |
Q.4. Sketch the appropriate diagrams showing following chromosomal aberrations:
i. deletion
ii. inversion
[Please draw a diagram showing a chromosome segment being lost (Deletion) and a segment rotating 180 degrees (Inversion).]i. Deletion: A segment of the chromosome (e.g., segment D) is lost.
ii. Inversion: A segment of the chromosome breaks, rotates 180°, and rejoins (e.g., B-C-D becomes D-C-B).
Q.5. Observe the following diagram of double circulation and identify A, B, C and D:
- A: Pulmonary artery
- B: Dorsal Aorta (Systemic Aorta)
- C: Body organs / Systemic capillaries
- D: Lungs (Pulmonary capillaries)
Q.6. i. Select the names of fresh-water fishes from the given list:
Sardinella, Rastrelliger, Cirrhina, Harpadon, Labeo
ii. Write the economic importance of Lac (Any Two).
2. It is used in the preparation of inks, polishes, and sealing wax.
Q.7. i. Define the term − Ecological succession.
ii. What is the reason of eutrophication?
Q.8. i. Mention any two ill-effects of UV-rays on human beings.
2. It causes inflammation of the cornea (snow blindness) or cataract.
ii. Give significance of Ecosan.
Q.9. What are oral vaccines? Enlist the benefits of oral vaccines.
Benefits:
1. They are easy to administer and painless (no needles required).
2. They are cost-effective and suitable for mass immunization campaigns (e.g., Pulse Polio).
3. They stimulate mucosal immunity (IgA production) in the gut.
Q.10. What is vernalization? Give the advantages of vernalization.
Advantages:
1. It prevents precocious reproductive development late in the growing season.
2. It enables plants to have sufficient time to reach maturity.
3. It can induce early flowering in some plants.
Q.11. Enlist the causes of biodiversity losses.
1. Habitat loss and fragmentation.
2. Over-exploitation.
3. Alien species invasions.
4. Co-extinctions.
Q.12. Give role of hormones Relaxin and Inhibin.
Inhibin: It is secreted by Sertoli cells in males and Granulosa cells in females. It inhibits the secretion of FSH (Follicle Stimulating Hormone) from the pituitary gland to regulate spermatogenesis or follicular development.
Q.13. Sketch and label the diagram of a stoma showing kidney − shaped guard cells.
Labels to include:
- Kidney-shaped Guard cells
- Stomatal pore (aperture)
- Chloroplasts (inside guard cells)
- Subsidiary cells (surrounding guard cells)
- Epidermal cells
Q.14. Explain in brief the process of southern blotting and hybridization in DNA fingerprinting.
Hybridization: The membrane containing the DNA fragments is exposed to radioactive DNA probes (single-stranded DNA sequences complementary to the VNTRs). These probes bind (hybridize) to specific complementary DNA sequences on the membrane. The hybridized fragments can then be detected using autoradiography.
Attempt any EIGHT of the following questions: [24]
Q.15. i. Define − Palaeontology.
ii. Give any four points of significance of palaeontology.
2. It helps in constructing the phylogeny (evolutionary history) of organisms.
3. It helps in the study of extinct organisms and their habits.
4. It connects links between different groups of organisms (e.g., Archaeopteryx connects reptiles and birds).
5. It helps in the study of the geological time scale.
Q.16. i. What is pollination?
ii. Differentiate between Anaemophily and Entomophily with reference to:
- a. pollinating agent
- b. stigma
- c. nectar
- d. fragrance
| Feature | Anaemophily (Wind Pollination) | Entomophily (Insect Pollination) |
|---|---|---|
| a. Pollinating agent | Wind | Insects |
| b. Stigma | Large, feathery, and exposed to trap pollen. | Sticky, often situated deep within the flower. |
| c. Nectar | Absent | Present (produced to attract insects) |
| d. Fragrance | Absent | Present (often sweet-smelling) |
Q.17. i. Differentiate between hypotonic and hypertonic solutions.
Hypertonic solution: A solution having a higher concentration of solutes (and lower water potential) compared to the cell sap.
ii. Mention the effect of exo-osmosis and endo-osmosis on shape of the cell.
Endo-osmosis: Causes the cell to swell and become turgid.
iii. Give one difference between symplast and apoplast pathway.
Apoplast pathway: Water moves through the non-living parts (cell walls and intercellular spaces). It is faster.
Q.18. i. Mention the control measures to prevent ascariasis.
2. Washing vegetables and fruits thoroughly before consumption.
3. Proper disposal of human excreta and preventing soil pollution.
ii. With appropriate terms, complete the following chart and rewrite it.
| Sr. No. | Name of disease | Name of pathogen |
|---|---|---|
| a. | Amoebiasis (Amoebic Dysentery) | Entamoeba histolytica |
| b. | Typhoid | Salmonella typhi |
| c. | Filariasis (Elephantiasis) | Wuchereria bancrofti |
| d. | Malaria | Plasmodium species |
Q.19. i. Define − Adaptation.
ii. Explain any two adaptations in Opuntia and Seal.
2. Stems are modified into flattened, green structures (phylloclades) to perform photosynthesis and store water.
Seal (Aquatic Mammal in cold climate): 1. They possess a thick layer of fat (blubber) below their skin that acts as an insulator to reduce the loss of body heat.
Q.20. Match the disease resistant varieties given in Column-I with the crops in Column-II and rewrite:
| Column-I (Variety) | Column-II (Crop) |
|---|---|
| i. Himgiri | b. Wheat |
| ii. Pusa shubhra | c. Cauliflower |
| iii. Pusa sadabahar | a. Chilli |
Q.21. i. Explain the qualitative and quantitative aspects of growth phenomenon.
Qualitative aspect: Growth involves development, differentiation, and change in the form or function of cells and tissues leading to maturity.
ii. Explain the phase of cell maturation.
Q.22. i. What is co-dominance?
ii. If a red colored female cattle is crossed with a white male cattle, what will be the appearance of progeny in F2 generation? Show the genotypes with the help of a chart.
F1 Generation: All Roan (RW)
F2 Generation (Selfing F1): RW × RW
Chart:
| Gametes | R | W |
|---|---|---|
| R | RR (Red) | RW (Roan) |
| W | RW (Roan) | WW (White) |
Red : Roan : White = 1 : 2 : 1.
Q.23. i. Give any two involuntary vital functions of medulla oblongata.
2. Regulation of respiration (Respiratory center).
(Other functions: Vasomotor activities, peristalsis).
ii. Mention two functions of spinal cord.
2. Acting as a center for spinal reflexes.
Q.24. i. Define − Transcription.
ii. Write anticodons for the following triplet codons:
AUG, GAG, CUA, CCU
- AUG → UAC
- GAG → CUC
- CUA → GAU
- CCU → GGA
Q.25. i. Mention the position of the following in human heart:
a. Eustachian valve
b. Bicuspid valve
b. Bicuspid valve (Mitral valve): Located between the left atrium and the left ventricle.
ii. Differentiate between open and closed circulation with reference to:
a. blood pressure
b. exchange of material
b. Exchange of material: In open circulation, exchange occurs directly between blood and cells/tissues. In closed circulation, exchange occurs through the walls of capillaries.
Q.26. Draw a neat and proportionate diagram of Graafian follicle and label oocyte and antrum. Explain its structure in brief.
Labels: Secondary Oocyte, Antrum, Theca externa, Theca interna, Membrana Granulosa, Cumulus oophorus, Zona pellucida.
The Graafian follicle is a mature ovarian follicle. It consists of an outer protective layer called Theca externa and an inner vascular layer called Theca interna. Inside this, there are follicular cells forming the Membrana Granulosa. A large fluid-filled cavity called the Antrum (filled with liquor folliculi) is present. The secondary oocyte is situated eccentrically and is surrounded by a group of cells called Cumulus oophorus (or Discus proligerus). The oocyte is covered by a non-cellular layer called Zona pellucida.
Attempt any THREE of the following questions: [12]
Q.27. i. What is placenta?
ii. Give reason − Placenta is considered as a temporary endocrine gland.
iii. Give significance of hCG.
Q.28. Describe in brief the structural and hormonal changes during ovarian cycle.
1. Menstrual Phase (Days 1-5):
If fertilization does not occur, the corpus luteum degenerates. Progesterone and estrogen levels fall. This triggers the breakdown of the endometrium.
2. Follicular Phase (Days 5-13):
Under the influence of FSH (Follicle Stimulating Hormone) from the pituitary, primary follicles in the ovary develop into mature Graafian follicles. The developing follicles secrete Estrogen, which helps in the regeneration of the endometrium.
3. Ovulatory Phase (Day 14):
Estrogen levels peak, stimulating a surge in LH (Luteinizing Hormone). This LH surge causes the rupture of the Graafian follicle and the release of the secondary oocyte (ovulation).
4. Luteal Phase (Days 15-28):
Under the influence of LH, the remaining cells of the ruptured follicle transform into the Corpus Luteum. The Corpus Luteum secretes large amounts of Progesterone (and some estrogen), which maintains the endometrium for implantation. If fertilization does not occur, the Corpus Luteum degenerates into a white scar called Corpus Albicans.
Q.29. i. Name the formed elements which are useful in blood coagulation. Give its normal number per cubic milimeter (mm³) in human blood.
Normal number: 1.5 to 3.5 lakhs / mm³ (150,000 to 350,000 / mm³).
ii. Comment on the shape and secretion of the above mentioned formed elements.
Secretion: They release clotting factors like Thromboplastin (Platelet factor 3).
iii. Explain in brief the mechanism of blood coagulation.
2. Thromboplastin initiates the formation of the enzyme complex Prothrombinase (or Thrombokinase).
3. Prothrombinase converts inactive Prothrombin into active Thrombin in the presence of Calcium ions (\(Ca^{++}\)).
4. Thrombin converts soluble Fibrinogen protein into insoluble Fibrin threads.
5. These fibrin threads form a mesh that traps blood cells, forming a clot (coagulum).
Q.30. i. Give full form of the cloning vectors BAC and YAC.
YAC: Yeast Artificial Chromosome.
ii. Write the appropriate palindrome for Eco RI and indicate by an arrow its recognition sequence.
5' — G ↓ A A T T C — 3'3' — C T T A A ↑ G — 5'(The arrows indicate the cut site between G and A).
iii. Give any four uses of gene therapy.
2. Treatment of Cystic Fibrosis.
3. Treatment of Haemophilia.
4. Treatment of certain cancers (using suicide genes).
5. Treatment of Parkinson’s disease.
Q.31. Explain any four contrivances to prevent self pollination in plants with an appropriate example of each type.
2. Dichogamy: In bisexual flowers, anthers and stigma mature at different times.
- Protandry: Anthers mature first. Example: Sunflower, Disc florets.
- Protogyny: Stigma matures first. Example: Michelia, Gloriosa.
3. Prepotency: Pollen grains of another flower germinate more rapidly over the stigma than the pollen grains from the same flower. Example: Apple.
4. Heterostyly (Heteromorphy): Plants produce flowers with different lengths of styles and stamens, preventing pollen from reaching the stigma of the same flower. Example: Primula (Primrose).
5. Herkogamy: Physical barriers prevent self-pollination. Example: Calotropis (Pentangular stigma positioned above anthers).
6. Self-sterility (Self-incompatibility): Pollen grains fail to germinate on the stigma of the same flower due to genetic mechanisms. Example: Tobacco, Thea.