SET 1
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PSEB BIOLOGY 10+2 SEPTEMBER EXAM 2025
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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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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Embryo sac in angiosperms is formed from:
(a) Microspore (b) Megaspore (c) Endosperm (d) Ovule -
In mammals, fertilisation occurs in:
(a) Cervix (b) Vagina (c) Fallopian tube (d) Uterus -
In mango, the edible part is:
(a) Mesocarp (b) Endosperm (c) Endocarp (d) Seed coat -
Surgical method of birth control in females is:
(a) Vasectomy (b) Tubectomy (c) Condom (d) IUD -
Which hormone induces ovulation?
(a) Estrogen (b) LH (c) FSH (d) Oxytocin -
The stage of embryo with hollow ball of cells:
(a) Morula (b) Blastula (c) Gastrula (d) Zygote -
AIDS is caused by:
(a) HIV (b) HBV (c) HCV (d) Plasmodium -
Down’s syndrome is caused by:
(a) Monosomy 21 (b) Trisomy 21 (c) Deletion of X (d) Extra Y chromosome -
Which group is universal donor?
(a) A (b) B (c) AB (d) O -
In Lac operon, genes are switched on when:
(a) Lactose present (b) Glucose absent (c) Both (a) & (b) (d) None -
Which of the following is an example of active immunity?
(a) Vaccination (b) Colostrum (c) Serum therapy (d) Antitoxin -
In industrial production, penicillin is obtained from:
(a) Bacteria (b) Yeast (c) Penicillium fungus (d) Virus
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(b) Fill in the blanks (4 × 1 = 4 marks):
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Process of formation of sperm from spermatids is called _______.
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_______ is the functional unit of heredity.
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Extra-embryonic membrane that surrounds embryo and protects it is _______.
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In sewage treatment plant, activated sludge contains large number of _______.
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(c) True/False (4 × 1 = 4 marks):
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Placenta is formed only from maternal tissue. ( )
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Haemophilia is an autosomal disorder. ( )
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DNA replication in eukaryotes is semi-conservative. ( )
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Antibiotics are effective against both bacteria and viruses. ( )
Section – B (2 × 10 = 20 Marks)
Q.2. Define double fertilisation in angiosperms.
Q.3. Draw a labelled diagram of T.S. of anther.
OR Draw L.S. of an ovule.
Q.4. Define menarche and menopause.
OR Write two differences between spermatogenesis and oogenesis.
Q.5. Write two functions of placenta in humans.
Q.6. Define adaptive radiation with an example.
Q.7. What is corpus luteum? Mention its role.
Q.8. Differentiate between morula and blastula (any two points).
Q.9. Expand IVF and ZIFT. Write significance of amniocentesis.
OR What are Leydig cells? Mention their role.
Q.10. What are multiple alleles? Give one example.
OR Define codominance with an example.
Q.11. Write two roles of ribosomes during protein synthesis.
Q.12. Define nucleosome.
OR Define Okazaki fragments.
Section – C (3 × 5 = 15 Marks)
Q.13. Differentiate between template strand and coding strand.
OR Name the enzyme which joins DNA fragments. Write its role.
Q.14. What is Human Genome Project? Why is it called a mega project?
Q.15. Write four uses of microbes in industry and food.
OR Describe the role of microbes in sewage treatment.
Q.16. Explain Darwin’s theory of natural selection with example.
Q.17. What are the salient features of genetic code? (any four)
Section – D (5 × 3 = 15 Marks)
Q.18. Describe process of oogenesis in humans with a neat diagram.
OR Explain menstrual cycle in human female with diagram.
Q.19. Draw a well-labelled diagram of structure of maize seed.
OR Explain development of female gametophyte in angiosperms with diagram.
Q.20. (Comprehension from Ch.7 – Human Health & Disease)
Read the passage and answer:
“Tuberculosis (TB) is caused by Mycobacterium tuberculosis. It primarily infects lungs and spreads through air when an infected person coughs. Symptoms include persistent cough, fever, weight loss and fatigue. BCG vaccine provides protection. Antibiotics are used for treatment but drug-resistance is increasing.”
(i) Name the pathogen causing TB.
(ii) Mention two symptoms of TB.
(iii) How is TB transmitted?
(iv) Name one vaccine against TB.
(v) Why is drug resistance in TB a serious concern?
