BSEB MODEL QUESTION PAPER
INTERMEDIATE EXAMINATION – 2027
BIOLOGY (ELECTIVE)
I.Sc. (Theory)
Subject Code: 119
Time: 3 Hours 15 Minutes
Full Marks: 70
Instructions for the Candidates
- This question paper is divided into two sections: Section-A and Section-B.
- Section-A contains 70 objective type questions. Answer any 35 questions.
- Each objective question carries 1 mark.
- If more than 35 objective questions are answered, only the first 35 answers will be evaluated.
- Section-B contains 20 short-answer questions. Answer any 10 questions.
- Each short-answer question carries 2 marks.
- Section-B also contains 6 long-answer questions. Answer any 3 questions.
- Each long-answer question carries 5 marks.
- Use of electronic devices is not permitted.
SECTION – A
Objective Type Questions
35 × 1 = 35
Objective Type Questions
35 × 1 = 35
Questions 1 to 70 have four options. Choose the correct option.
1. The basic unit of heredity is:
Answer: (B) Gene
2. Mendel performed his experiments mainly on:
Answer: (B) Garden pea
3. The phenotypic ratio in a typical Mendelian monohybrid cross is:
Answer: (C) 3 : 1
4. In humans, the male is:
Answer: (B) Heterogametic
5. How many genotypes are possible for the ABO blood group system?
Answer: (C) 6
6. The scientist who prepared the first genetic recombination map was:
Answer: (B) Sturtevant
7. RNA contains which pentose sugar?
Answer: (B) Ribose
8. Which nitrogenous base is present in RNA but absent in DNA?
Answer: (C) Uracil
9. DNA replication is generally:
Answer: (C) Semi-conservative
10. The enzyme responsible for joining DNA fragments is:
Answer: (A) DNA ligase
11. The process by which different species evolve from a common ancestral species in different habitats is called:
Answer: (B) Adaptive radiation
12. According to Oparin and Haldane, early Earth's atmosphere was:
Answer: (B) Reducing
13. DNA fingerprinting was developed by:
Answer: (A) Alec Jeffreys
14. In the lac operon, the repressor protein binds to the:
Answer: (B) Operator
15. Penicillin was discovered by:
Answer: (A) Alexander Fleming
16. Citric acid is commercially produced using:
Answer: (A) Aspergillus niger
17. Streptokinase is used as:
Answer: (A) Clot buster
18. Trichoderma is mainly used as a:
Answer: (A) Biocontrol agent
19. Which fungus forms mycorrhiza?
Answer: (A) Glomus
20. Blood circulation in humans was discovered by:
Answer: (A) William Harvey
21. Heroin is chemically obtained by acetylation of:
Answer: (B) Morphine
22. The spread of malignant cells to distant parts of the body is called:
Answer: (A) Metastasis
23. AIDS is caused by:
Answer: (B) HIV
24. Lymphocytes interact with antigens mainly in:
Answer: (A) Secondary lymphoid organs
25. Which of the following is an autoimmune disease?
Answer: (B) Rheumatoid arthritis
26. The predominant antibody present in colostrum is:
Answer: (A) IgA
27. Amoebic dysentery is caused by:
Answer: (B) Entamoeba histolytica
28. Typhoid is caused by:
Answer: (A) Salmonella typhi
29. Bt cotton contains genes obtained from:
Answer: (A) Bacillus thuringiensis
30. Mature insulin consists of:
Answer: (C) A and B chains linked by disulphide bonds
31. Which technique is based on antigen-antibody interaction?
Answer: (B) ELISA
32. RNA interference has been used to control:
Answer: (A) Meloidogyne incognita
33. Golden Rice is rich in:
Answer: (B) Provitamin A
34. PCR is used primarily for:
Answer: (A) DNA amplification
35. The plasmid used in recombinant DNA technology is commonly obtained from:
Answer: (A) Bacteria
36. The enzyme that joins a foreign DNA fragment with a vector is:
Answer: (A) DNA ligase
37. Hind II is an example of a:
Answer: (A) Restriction endonuclease
38. DNA fragments move towards the anode during gel electrophoresis because DNA is:
Answer: (B) Negatively charged
39. A cloning vector must possess:
Answer: (D) All of these
40. A commonly used vector for gene transfer into plant cells is:
Answer: (A) Agrobacterium tumefaciens
41. The enzyme used to break the bacterial cell wall during DNA isolation is:
Answer: (A) Lysozyme
42. Restriction endonucleases recognise specific:
Answer: (A) Palindromic DNA sequences
43. Asexual reproduction that mimics sexual reproduction is called:
Answer: (A) Apomixis
44. Apple is an example of:
Answer: (B) False fruit
45. In a typical mature dicot seed, the endosperm is usually:
Answer: (A) Absent
46. The scutellum of grasses represents the:
Answer: (B) Single cotyledon
47. Pollination through water occurs in:
Answer: (A) Zostera
48. Transfer of pollen from one flower to another flower of the same plant is:
Answer: (B) Geitonogamy
49. Human testes are located in the scrotum because it:
Answer: (B) Keeps the testes cooler than body temperature
50. Fertilisation in humans normally occurs in the:
Answer: (B) Ampullary-isthmic junction of fallopian tube
51. The correct sequence of spermatogenesis is:
Answer: (A)
52. The first menstrual cycle in a female is called:
Answer: (B) Menarche
53. Amniocentesis is used for:
Answer: (A) Detection of certain genetic disorders
54. Which factor generally contributes to population growth?
Answer: (C) Increase in reproductive-age population
55. Which of the following is a sexually transmitted infection?
Answer: (A) Gonorrhoea
56. Which plant is well known for reproducing only once during its lifetime?
Answer: (A) Bamboo
57. Opuntia was biologically controlled in Australia using:
Answer: (A) A moth
58. Predators help in maintaining:
Answer: (A) Species diversity
59. The interaction in which both species are negatively affected is:
Answer: (B) Competition
60. The relationship between clown fish and sea anemone is generally considered:
Answer: (A) Mutualism
61. India possesses approximately what percentage of the world's recorded species diversity?
Answer: (B) 8.1%
62. The 2002 World Summit on Sustainable Development was held at:
Answer: (B) Johannesburg
63. Which is a direct economic argument for biodiversity conservation?
Answer: (A) Medicinal resources
64. Which species became extinct mainly due to overexploitation?
Answer: (A) Steller's sea cow
65. The rate of production of organic matter during photosynthesis is called:
Answer: (A) Primary productivity
66. Gross primary productivity minus respiratory loss is:
Answer: (B) Net primary productivity
67. Which process is NOT a part of decomposition?
Answer: (D) Anabolism
68. Plants capture approximately what fraction of incident solar energy as photosynthetically active radiation?
Answer: (A) 2–10%
69. The detritus food chain begins with:
Answer: (B) Dead organic matter
70. Saheli is a:
Answer: (A) Non-steroidal oral contraceptive pill
SECTION – B
Short Answer Type Questions
10 × 2 = 20
Short Answer Type Questions
10 × 2 = 20
Answer any 10 questions. Each question carries 2 marks.
1. What is a sacred grove? Mention one importance of sacred groves.
Answer: A sacred grove is a patch of natural vegetation protected by local communities because of religious or cultural beliefs. It helps conserve local biodiversity and protects rare plants and animals.
2. Explain the pyramid of energy.
Answer: The pyramid of energy represents the amount of energy present at different trophic levels of an ecosystem. Energy decreases progressively from producers to higher trophic levels and the pyramid is always upright.
3. What is mutualism? Give one example.
Answer: Mutualism is an interaction in which both associated species benefit. For example, lichens show mutualism between an alga and a fungus.
4. What is the competitive exclusion principle?
Answer: The competitive exclusion principle states that two closely related species competing for exactly the same limiting resources cannot coexist indefinitely in the same habitat.
5. How are restriction endonucleases named?
Answer: Their names are derived from the genus, species and strain of the microorganism from which they are isolated, followed by a Roman numeral indicating the order of isolation.
6. What is downstream processing?
Answer: Downstream processing refers to the processes used for separation, purification and formulation of a desired biological product after its production by a biotechnological process.
7. What are somaclones?
Answer: Somaclones are plants regenerated from somatic cells through tissue culture. They are generally genetically similar to the parent plant, although useful variations may occur.
8. What is biopiracy? Give an example.
Answer: Biopiracy is the unauthorised use or commercial exploitation of biological resources or traditional knowledge without proper permission or benefit sharing. Commercial claims over traditional uses of neem or turmeric are commonly cited examples.
9. What is a flock?
Answer: A flock is a group of birds or other animals that live, move or feed together. Such grouping may provide advantages such as protection and efficient foraging.
10. What is a biofertilizer? Give two examples.
Answer: Biofertilizers are preparations containing living microorganisms that increase nutrient availability to plants. Examples include Rhizobium and Azotobacter.
11. What are cannabinoids?
Answer: Cannabinoids are biologically active compounds obtained from the Cannabis plant. They affect the nervous system and have been associated with effects such as altered perception and mood.
12. Define active immunity.
Answer: Active immunity develops when an individual's own immune system produces antibodies and memory cells in response to an antigen, either naturally through infection or artificially through vaccination.
13. What is the founder effect?
Answer: Founder effect is a form of genetic drift that occurs when a new population is established by a small number of individuals from a larger population. The new population may therefore have different allele frequencies.
14. What are homologous organs? Give an example.
Answer: Homologous organs have the same basic structural origin but may perform different functions. The forelimbs of humans and wings of bats are examples.
15. What are Expressed Sequence Tags?
Answer: Expressed Sequence Tags (ESTs) are short DNA sequences obtained from expressed genes, usually by sequencing cDNA. They help in identifying and studying expressed genes.
16. What is haemophilia?
Answer: Haemophilia is an inherited blood-clotting disorder in which clotting is impaired because of deficiency of a clotting factor. It is generally an X-linked recessive disorder.
17. What are Sertoli cells? Mention one function.
Answer: Sertoli cells are supporting cells present in the seminiferous tubules of testes. They nourish developing sperm cells and help regulate spermatogenesis.
18. Mention two functions of the placenta.
Answer: The placenta facilitates exchange of oxygen, nutrients and wastes between mother and foetus. It also acts as an endocrine tissue and secretes hormones such as hCG, hPL, oestrogens and progesterone.
19. What is double fertilisation? Where does it occur?
Answer: Double fertilisation is the occurrence of syngamy and triple fusion in the same embryo sac. It is a characteristic feature of angiosperms.
20. What is polyembryony? Give one example.
Answer: Polyembryony is the development of more than one embryo in a single seed. It occurs naturally in some citrus species.
SECTION – B
Long Answer Type Questions
3 × 5 = 15
Long Answer Type Questions
3 × 5 = 15
Answer any 3 questions. Each question carries 5 marks. Answer in about 120 words.
21. What is megasporogenesis? Describe the development of the embryo sac.
Answer:
Megasporogenesis is the process of formation of megaspores from a diploid megaspore mother cell in the ovule. The megaspore mother cell undergoes meiosis and produces four haploid megaspores. Usually, three megaspores degenerate and the remaining functional megaspore develops into the female gametophyte or embryo sac. The functional megaspore undergoes three successive mitotic divisions to form eight nuclei. These nuclei become organised into a typical seven-celled, eight-nucleate embryo sac. Three cells form the egg apparatus at the micropylar end, three antipodal cells occur at the chalazal end and two polar nuclei remain in the central cell.
22. Describe DNA replication and mention the roles of important enzymes.
Answer:
DNA replication is the process by which DNA produces an identical copy of itself. It is semi-conservative because each daughter DNA molecule contains one parental strand and one newly synthesised strand. Helicase unwinds the DNA double helix, while single-strand binding proteins stabilise the separated strands. Primase forms RNA primers. DNA polymerase adds nucleotides in the 5′→3′ direction. The leading strand is synthesised continuously, whereas the lagging strand is synthesised discontinuously as Okazaki fragments. DNA ligase joins the Okazaki fragments. Finally, the primers are removed and the gaps are filled with DNA.
23. Describe the human immune system.
Answer:
The immune system protects the body against pathogens and foreign substances. It includes lymphoid organs, immune cells and immune molecules. Primary lymphoid organs such as bone marrow and thymus are responsible for the formation and maturation of lymphocytes. Secondary lymphoid organs include lymph nodes, spleen and mucosal lymphoid tissues where lymphocytes interact with antigens. B lymphocytes produce antibodies and provide humoral immunity, whereas T lymphocytes are important in cell-mediated immunity. Innate immunity provides immediate, non-specific protection, while acquired immunity is specific and develops immunological memory. Vaccination can stimulate active acquired immunity against particular diseases.
24. Explain the major steps involved in recombinant DNA technology.
Answer:
Recombinant DNA technology involves isolation of DNA, cutting of DNA at specific sites using restriction endonucleases, amplification or preparation of the desired DNA fragment, and insertion of the fragment into a suitable vector. DNA ligase joins the foreign DNA with the vector to form recombinant DNA. The recombinant vector is introduced into a suitable host cell and transformed cells are selected using selectable markers. The selected cells are allowed to multiply and express the desired gene. Finally, the desired product is recovered and purified through downstream processing.
25. Explain the importance of biodiversity conservation and distinguish between in-situ and ex-situ conservation.
Answer:
Biodiversity conservation is necessary for maintaining ecological stability, genetic resources and ecosystem services. In-situ conservation means conserving organisms in their natural habitats. National parks, wildlife sanctuaries and biosphere reserves are examples of in-situ conservation. Ex-situ conservation means conserving organisms outside their natural habitats. Botanical gardens, zoological parks, seed banks and gene banks are examples. In-situ conservation allows species to continue their natural ecological interactions, whereas ex-situ conservation is especially useful when a species is highly threatened or its natural habitat is severely disturbed.
26. Explain the concept of ecological pyramids and describe the pyramid of energy.
Answer:
Ecological pyramids represent the relationship among different trophic levels of an ecosystem. They may represent number, biomass or energy. The pyramid of energy represents the amount of energy available at successive trophic levels. Producers form the first trophic level, followed by primary consumers, secondary consumers and higher consumers. At each trophic transfer, a large part of energy is lost, mainly as heat during metabolic activities. Therefore, energy decreases progressively from producers to higher trophic levels and the pyramid of energy is always upright.
OBJECTIVE ANSWER KEY
| Q. | Ans. | Q. | Ans. | Q. | Ans. | Q. | Ans. |
|---|---|---|---|---|---|---|---|
| 1 | B | 19 | A | 37 | A | 55 | A |
| 2 | B | 20 | A | 38 | B | 56 | A |
| 3 | C | 21 | B | 39 | D | 57 | A |
| 4 | B | 22 | A | 40 | A | 58 | A |
| 5 | C | 23 | B | 41 | A | 59 | B |
| 6 | B | 24 | A | 42 | A | 60 | A |
| 7 | B | 25 | B | 43 | A | 61 | B |
| 8 | C | 26 | A | 44 | B | 62 | B |
| 9 | C | 27 | B | 45 | A | 63 | A |
| 10 | A | 28 | A | 46 | B | 64 | A |
| 11 | B | 29 | A | 47 | A | 65 | A |
| 12 | B | 30 | C | 48 | B | 66 | B |
| 13 | A | 31 | B | 49 | B | 67 | D |
| 14 | B | 32 | A | 50 | B | 68 | A |
| 15 | A | 33 | B | 51 | A | 69 | B |
| 16 | A | 34 | A | 52 | B | 70 | A |
| 17 | A | 35 | A | 53 | A | ||
| 18 | A | 36 | A | 54 | C |