✦ PSEB BIOLOGY 10+2 SEPTEMBER EXAM 2025 SET 2 ✦
Class: 10+2 | Subject: Biology | Time: 3 Hours | M.M. 70
General Instructions
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The question paper has four sections A, B, C, D consisting of 19 questions.
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All questions are compulsory. Internal choice is provided where mentioned.
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The use of a simple calculator is allowed.
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Draw neat and labelled diagrams wherever necessary.
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The marks for each question are indicated.
Section – A (1 × 20 = 20 Marks)
Q.1. Answer the following (20 parts, each 1 mark).
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(a) Multiple Choice Questions (12 × 1 = 12 marks):
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Male gametes in angiosperms are produced by:
(a) Microspore mother cell (b) Generative cell (c) Vegetative cell (d) Endosperm cell -
Which layer of uterus is shed during menstruation?
(a) Endometrium (b) Myometrium (c) Perimetrium (d) None -
Copper-T prevents pregnancy by:
(a) Inhibiting ovulation (b) Preventing implantation (c) Blocking fertilisation (d) Increasing sperm motility -
Which disease is not sexually transmitted?
(a) Gonorrhoea (b) Syphilis (c) Tuberculosis (d) AIDS -
Turner's syndrome is due to:
(a) Trisomy 21 (b) XO condition (c) XXY condition (d) Extra Y -
The nitrogenous base absent in RNA is:
(a) Uracil (b) Thymine (c) Adenine (d) Cytosine -
In Griffith’s experiment, the transforming principle was later proved as:
(a) RNA (b) Protein (c) DNA (d) Carbohydrate -
The term “survival of the fittest” was given by:
(a) Lamarck (b) Darwin (c) Wallace (d) Mendel -
Immunity acquired by colostrum in infants is:
(a) Active immunity (b) Innate immunity (c) Passive immunity (d) Autoimmunity -
Which microorganism is used in production of citric acid?
(a) Aspergillus niger (b) Penicillium (c) Saccharomyces (d) Lactobacillus -
Which vaccine is given for polio?
(a) BCG (b) OPV (c) DPT (d) MMR -
Which of the following is a biological control agent?
(a) Bacillus thuringiensis (b) Rhizobium (c) E. coli (d) Nostoc
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(b) Fill in the blanks (4 × 1 = 4 marks):
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The fusion of male gamete with secondary nucleus is called _______.
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_______ acts as the barrier in reverse transcription process in retroviruses.
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The Hardy–Weinberg principle gives information about _______ of a population.
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The microorganism used in alcohol production is _______.
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(c) True/False (4 × 1 = 4 marks):
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Syngamy and triple fusion occur inside ovule. ( )
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Colostrum is rich in IgG antibodies. ( )
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DNA ligase joins Okazaki fragments during replication. ( )
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Yeast is used in production of biogas. ( )
Section – B (2 × 10 = 20 Marks)
Q.2. Define pollination. Write two differences between autogamy and xenogamy.
Q.3. Draw a well-labelled diagram of L.S. of maize grain.
OR Draw T.S. of anther showing its four microsporangia.
Q.4. What is parturition? Which hormone induces it?
OR Differentiate between spermiogenesis and spermatogenesis.
Q.5. Write two causes of infertility in humans.
Q.6. Define analogous organs with example.
Q.7. What is test cross? Write its significance.
Q.8. Explain the role of ribosomal RNA in protein synthesis.
OR What is replication fork?
Q.9. Define mutation. Give one example.
OR Write any two differences between monohybrid and dihybrid cross.
Q.10. What is vaccine? How does it provide immunity?
Q.11. What are biofertilisers? Give one example.
OR Write two advantages of biogas over conventional fuel.
Section – C (3 × 5 = 15 Marks)
Q.12. Differentiate between continuous variation and discontinuous variation.
OR Define linkage and recombination.
Q.13. What is genetic drift? Explain with an example.
Q.14. Describe salient features of genetic code.
Q.15. Write four applications of microbes in industrial products.
OR Explain briefly the role of microbes in sewage treatment.
Q.16. State the main postulates of Darwin’s theory of natural selection.
Section – D (5 × 3 = 15 Marks)
Q.17. Explain gametogenesis in humans with neat labelled diagram.
OR Describe menstrual cycle in human females with diagram.
Q.18. Draw a neat diagram of female reproductive system.
OR Explain double fertilisation in angiosperms with diagram.
Q.19. (Comprehension from Ch.7 – Human Health & Disease)
Read the passage and answer:
“Malaria is caused by Plasmodium species and transmitted by female Anopheles mosquito. The parasites multiply in liver and infect RBCs, leading to cycles of chills and fever. Preventive measures include mosquito control and prophylactic drugs.”
(i) Name the pathogen causing malaria.
(ii) Which vector transmits malaria?
(iii) Mention two symptoms of malaria.
(iv) Name the organ where parasite multiplies first.
(v) Suggest two preventive measures for malaria.
