Class 12/Question Bank/Competency Based
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
BioNotesBioNotesCreated by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Online
Competency Based Questions on Sexual Reproduction in Flowering Plants
1. Analyze the Scenario: A botanist observes that a particular plant species produces two types of flowers: one type that never opens (Cleistogamous) and another type that opens normally (Chasmogamous). Which of the following is most likely true? a) The plant relies solely on xenogamy. b) The closed flowers ensure heterozygosity. c) The plant produces pure lines for traits in the closed flowers. d) The open flowers are incapable of setting seeds.
2. Assertion (A): Apomictic seeds are highly advantageous for the hybrid seed industry. Reason (R): Apomixis prevents the segregation of characters in the hybrid progeny. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is false but R is true.
3. Evaluate the Impact: A farmer plants only female papaya plants to maximize yield but observes zero fruit set. What is the fundamental biological error? a) Papaya is monoecious. b) Papaya is dioecious; he ignored the need for male plants for pollination. c) Papaya is parthenocarpic. d) Papaya flowers are cleistogamous.
4. Assertion (A): Continued self-pollination often leads to inbreeding depression. Reason (R): Self-pollination introduces new genetic variations. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is false but R is true.
5. Predict the Outcome: If a scientist removes the filiform apparatus from the synergids before pollination, what will happen? a) The egg cell will die. b) The pollen tube will fail to enter the synergid. c) The antipodal cells will proliferate. d) Double fertilization will occur twice.
6. Analyze the Adaptation: A plant has flowers that are dull-colored, produce a strong fruity/fermenting odor, and bloom only at night. Which pollinator is it adapted for? a) Bees b) Wind c) Bats d) Birds
7. Calculation: If a fruit contains 60 seeds, what is the minimum number of meiotic divisions required to produce them? a) 60 b) 75 c) 120 d) 90
8. Assertion (A): The endosperm in angiosperms is typically triploid (3n). Reason (R): It is formed by the fusion of one male gamete with two polar nuclei. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is false but R is true.
9. Identify the mismatch: Which pair is correct? a) Light, non-sticky pollen - Entomophily b) Long, ribbon-like pollen with mucilage - Hydrophily c) Bright red flowers, no scent - Chiropterophily d) Feathery stigma - Zoophily
10. Critical Thinking: Evolutionary advantage of coleoptile and coleorhiza in monocots? a) Nutrition. b) Photosynthesis. c) Physical protection to the delicate plumule and radicle during soil penetration. d) Nitrogen fixation.
11. Assertion (A): Emasculation is necessary in artificial hybridization of papaya. Reason (R): Papaya plants produce unisexual flowers. a) Both A and R are true. b) Both A and R are true but R is not explanation. c) A is true but R is false. d) A is false but R is true.
12. Analyze the structure: Premature degeneration of the Tapetum in an anther leads to: a) Delayed dehiscence. b) Sterile pollen grains due to lack of nutrition. c) Thickened epidermis. d) Fast cell division.
13. Application: Sequence for hybridizing a self-pollinating crop? a) Emasculation -> Bagging -> Pollination -> Rebagging b) Bagging -> Emasculation -> Pollination -> Rebagging
Vanilla is an orchid native to Mexico, pollinated by Melipona bees. In Madagascar, it grows but sets no fruit naturally.
14. Analyze: Why failure in Madagascar?
15. Evaluate: Hand-pollination involves lifting a flap (rostellum) to touch anther to stigma. What barrier is this?
In Wheat, temperatures >35°C lead to shriveled, non-viable pollen.
16. Diagnose: Failure point?
17. Hypothesize: Which anther layer is damaged?
Farmers save seeds from hybrid tomatoes, but the F2 plants show loss of yield and variation.
18. Explain: Why loss of hybrid vigor?
19. Propose: Biological solution to "fix" the vigor?
20. Designing an Experiment: Pollinator identification.
21. Journey of the Male Gamete (Concept Map):
22. Formulating a Hypothesis: Desert seed germination.
23. Analyzing & Redesigning: Urban allergies (All-male trees).