🧬 Biology MCQ Questions
Set – 2 | General Science Practice for Competitive Exams
Strengthen concepts with exam-oriented Biology MCQs and instant answer checks
Q11. Tearing of eyes while cutting onion is mainly due to the formation of which irritant compound?
- (A) Sulphuric acid
- (B) Sulfenic acid
- (C) Hydrochloric acid
- (D) Acetic acid
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Correct answer is Sulfenic acid. It is a volatile irritant released when onion cells are damaged.
Q12. Which plant part plays the most crucial role in sexual reproduction and continuation of plant species?
- (A) Root
- (B) Stem
- (C) Leaf
- (D) Flower
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Correct answer is Flower. Flowers contain reproductive organs of plants.
Q13. The characteristic pungent taste of chilli peppers is caused by:
- (A) Capsaicin
- (B) Carotene
- (C) Lycopene
- (D) Xanthophyll
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Correct answer is Capsaicin. It is responsible for the spicy sensation.
Q14. The chemical substance responsible for the burning sensation of red chillies belongs to which category?
- (A) Alkaloid
- (B) Glycoside
- (C) Protein
- (D) Enzyme
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Correct answer is Alkaloid. Capsaicin is an alkaloid responsible for the burning sensation.
Q15. Commercial silk fibre is obtained from silkworm at which developmental stage?
- (A) Egg stage
- (B) Adult moth
- (C) Larval stage
- (D) Pupal stage
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Correct answer is Pupal stage. Silk fibres are obtained from cocoons formed in the pupal stage.
Q16. Lichens represent a symbiotic relationship between:
- (A) Algae and moss
- (B) Fungus and algae
- (C) Bacteria and fungus
- (D) Algae and protozoa
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Correct answer is Fungus and algae. Fungus provides shelter, algae prepares food.
Q17. The organisms that act as pioneers in ecological succession on bare rocks are mainly:
- (A) Mosses
- (B) Algae
- (C) Lichens
- (D) Fungi
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Correct answer is Lichens. Lichens are pioneer species that colonize bare rocks and initiate ecological succession.
Q18. Noscapine, a medicinal alkaloid, is extracted from which plant source?
- (A) Ephedra
- (B) Opium poppy
- (C) Basil
- (D) Eucalyptus
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Correct answer is Opium poppy. Noscapine is an alkaloid derived from Papaver somniferum (opium poppy) used medicinally.
Q19. Heroin is a semi-synthetic drug derived from:
- (A) Cannabis sativa
- (B) Papaver somniferum
- (C) Nicotiana tabacum
- (D) Areca catechu
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Correct answer is Papaver somniferum. Heroin is derived from morphine, obtained from opium poppy.
Q20. Morphine is obtained from which part of the opium poppy plant?
- (A) Leaves
- (B) Stem
- (C) Unripe fruit (capsule)
- (D) Flower
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Correct answer is Unripe fruit (capsule). Morphine is obtained from the latex of unripe opium poppy capsules.
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