2nd PUC Biology Model Question Paper 2026 With Answer Key

II PUC MODEL QUESTION PAPER 2026

BIOLOGY (Subject Code: 36)

Maximum Marks: 70     Time: 3 Hours 15 Minutes

(15 minutes for reading the question paper)

Instructions:
1. The question paper has five parts. All parts are compulsory.
2. Draw neat, labelled diagrams wherever necessary.
3. Part-A: 20 marks (15 MCQs + 5 Fill-ups).
4. Part-E: Numerical/Reasoning-based (show all steps).

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PART - A

I. Select the correct option. (15 × 1 = 15)

1. The process of separation of gametes during meiosis is called:

a) Synapsis b) Disjunction c) Crossing over d) Chiasmata

2. Which is a secondary pollutant?

a) CO b) PAN c) SO₂ d) NO₂

3. The embryonic tissue that gives rise to connective tissue is:

a) Ectoderm b) Endoderm c) Mesoderm d) Pachyderm

4. The functional unit of ecology is:

a) Population b) Community c) Ecosystem d) Biosphere

5. The enzyme that joins Okazaki fragments is:

a) Helicase b) Primase c) DNA ligase d) Topoisomerase

6. The hormone responsible for milk ejection is:

a) Prolactin b) Oxytocin c) Estrogen d) Progesterone

7. Which one is a C₄ plant?

a) Wheat b) Maize c) Pea d) Mango

8. The vector of dengue fever is:

a) Anopheles b) Aedes c) Culex d) Sandfly

9. The pyramid of energy is always:

a) Inverted b) Upright c) Spindle d) Irregular

10. The genetic material in TMV is:

a) ssDNA b) dsDNA c) ssRNA d) dsRNA

11. The codon AUG codes for:

a) Phenylalanine b) Methionine c) Termination d) Leucine

12. The part of brain that controls hunger is:

a) Cerebellum b) Hypothalamus c) Medulla d) Pons

13. The immunoglobulin present in colostrum is:

a) IgG b) IgA c) IgM d) IgE

14. The first National Park in India is:

a) Kaziranga b) Jim Corbett c) Gir d) Bandipur

15. The term ‘biome’ was coined by:

a) Odum b) Clements c) Tansley d) Warming

II. Fill in the blanks. (5 × 1 = 5)

16. The process of conversion of nitrate to nitrogen gas is .

17. The male gametophyte in angiosperms is .

18. The causative agent of amoebic dysentery is .

19. The type of pollination in which pollen grains are transferred by wind is .

20. The hormone that regulates blood calcium level is .

PART - B

Answer any FIVE. (5 × 2 = 10)

21. Define embryology. Name the scientist who coined the term.

22. What are homologous organs? Give two examples.

23. Mention any four greenhouse gases.

24. Differentiate between ex situ and in situ conservation.

25. Draw a neat labelled diagram of T.S. of anther.

26. What is apomixis? Give an example.

27. Name the two hormones secreted by pancreas. Mention their function.

28. What are STDs? Give two examples.

PART - C

Answer any FIVE. (5 × 3 = 15)

29. Explain the structure of tRNA with diagram.

30. Describe the role of microbes in sewage treatment.

31. Explain double fertilization with diagram.

32. Write a note on menstrual cycle in human female.

33. Explain the mechanism of sex determination in humans.

34. What is ecological succession? Explain its types.

35. Mention any six benefits of transgenic animals.

PART - D

Answer any THREE. (3 × 5 = 15)

36. Explain the law of segregation with a monohybrid cross.

37. Describe the structure of anatropous ovule with a neat labelled diagram.

38. Explain the structure and functions of brain in humans.

39. With a neat labelled diagram explain the working of human heart.

40. Describe the nitrogen cycle with a diagram.

PART - E

Answer any THREE. (3 × 5 = 15)

41. Explain DNA replication with diagram (semi-conservative model).

42. Describe the lac operon model of gene regulation.

43. Explain any five methods of contraception.

44. Write a note on: (a) Down syndrome (b) Turner syndrome (c) Klinefelter syndrome

45. Explain the process of recombinant DNA technology (steps only with diagram).

46. What is biodiversity hotspot? Name any four hotspots in India.

Note: This model paper is prepared strictly according to the latest Karnataka PUC blueprint and previous year question paper pattern (2025). For official updates, visit the Department of Pre-University Education website.

DETAILED ANSWER KEY - BIOLOGY 2026 (KSEAB)

1. (b) Disjunction

2. (b) PAN (Peroxyacetyl nitrate)

3. (c) Mesoderm

4. (c) Ecosystem

5. (c) DNA ligase

6. (b) Oxytocin

7. (b) Maize

8. (b) Aedes aegypti

9. (b) Upright

10. (c) ssRNA

11. (b) Methionine

12. (b) Hypothalamus

13. (b) IgA

14. (b) Jim Corbett (1936)

15. (b) Clements

16. Denitrification

17. Pollen grain

18. Entamoeba histolytica

19. Anemophily

20. Calcitonin / Parathormone

21. Study of embryo development. Coined by Karl Ernst von Baer.

22. Organs with same origin but different function.
Ex: Forelimb of whale & bat, vertebrate heart.

23. CO₂, CH₄, N₂O, CFC, Ozone, Water vapour.

31. Double fertilization:
1. Syngamy → 2n zygote
2. Triple fusion → 3n PEN (primary endosperm nucleus)
Diagram: Pollen tube → 2 male gametes → one fuses with egg, one with polar nuclei.

36. Law of segregation: Alleles separate during gamete formation.
Monohybrid cross (Tt × Tt) → 3:1 phenotypic ratio
Punnett square shown in exam.

39. Human heart diagram (4 chambers, valves, aorta, vena cava, coronary arteries labelled).
Double circulation: Pulmonary & systemic.
Cardiac cycle: 0.8 sec.

41. DNA replication (semi-conservative):
Steps: Unwinding → Unzipping → Primer → Leading & lagging strand → Okazaki fragments → Ligase.
Diagram with replication fork.

42. Lac operon: Repressor, operator, promoter, structural genes (z, y, a).
In absence of lactose → repressor binds → no transcription.
In presence → allolactose → repressor inactive → transcription.

43. Five methods:
1. Condoms
2. Oral pills
3. IUD (Cu-T)
4. Tubectomy
5. Vasectomy

46. Biodiversity hotspot: High endemism + high threat.
Four in India: Western Ghats, Eastern Himalayas, Indo-Burma, Sundaland.

ALL ANSWERS AS PER KARNATAKA PUC 2026 MARKING SCHEME
Use this for self-evaluation & board exam practice!