You can also check: MPSC PYQs for General Science
Photosynthesis
1. Photosynthesis mainly takes place in which organelle of a plant cell?
(A) Mitochondria
(B) Chloroplast
(C) Ribosome
(D) Golgi apparatus
Answer: (B) Chloroplast
Explanation: Chloroplasts contain chlorophyll and are the primary sites of photosynthesis.
2. Which gas is absorbed by green plants during photosynthesis?
(A) Oxygen
(B) Nitrogen
(C) Carbon dioxide
(D) Hydrogen
Answer: (C) Carbon dioxide
3. The oxygen released during photosynthesis mainly comes from:
(A) Carbon dioxide
(B) Water
(C) Glucose
(D) Chlorophyll
Answer: (B) Water
Explanation: During the light-dependent reactions, water is split and oxygen is released.
4. Which pigment is primarily responsible for trapping light energy during photosynthesis?
(A) Haemoglobin
(B) Chlorophyll
(C) Melanin
(D) Keratin
Answer: (B) Chlorophyll
5. Which of the following factors can directly affect the rate of photosynthesis?
(A) Light intensity
(B) Carbon dioxide concentration
(C) Water availability
(D) All of the above
Answer: (D) All of the above
Respiration
6. Cellular respiration in plants primarily releases:
(A) Nitrogen
(B) Energy
(C) Chlorophyll
(D) Water only
Answer: (B) Energy
7. The main site of aerobic respiration in a plant cell is the:
(A) Chloroplast
(B) Mitochondrion
(C) Ribosome
(D) Vacuole
Answer: (B) Mitochondrion
8. Which gas is consumed during aerobic respiration?
(A) Carbon dioxide
(B) Oxygen
(C) Nitrogen
(D) Hydrogen
Answer: (B) Oxygen
9. During respiration, glucose is ultimately broken down to release:
(A) Energy
(B) Chlorophyll
(C) Nitrogen
(D) Cellulose
Answer: (A) Energy
Transpiration
10. The loss of water vapour from the aerial parts of plants is called:
(A) Respiration
(B) Transpiration
(C) Photosynthesis
(D) Translocation
Answer: (B) Transpiration
11. Transpiration mainly occurs through tiny pores called:
(A) Villi
(B) Stomata
(C) Nephrons
(D) Lenticels only
Answer: (B) Stomata
12. Which condition generally increases the rate of transpiration?
(A) High humidity
(B) Strong wind
(C) Low temperature
(D) Darkness
Answer: (B) Strong wind
Explanation: Wind removes water vapour surrounding the leaf, maintaining a concentration gradient that promotes water loss.
13. Which plant structure regulates the opening and closing of stomata?
(A) Guard cells
(B) Root hairs
(C) Xylem cells
(D) Phloem cells
Answer: (A) Guard cells
Plant Hormones
14. Which plant hormone promotes cell elongation and is strongly associated with phototropism?
(A) Auxin
(B) Cytokinin
(C) Ethylene
(D) Abscisic acid
Answer: (A) Auxin
15. A plant shoot bends toward a source of light mainly because of the action of:
(A) Auxin
(B) Ethylene
(C) Cytokinin
(D) Abscisic acid
Answer: (A) Auxin
Explanation: Auxin redistribution causes greater cell elongation on the shaded side, causing the shoot to bend toward light.
16. Which plant hormone promotes fruit ripening?
(A) Auxin
(B) Ethylene
(C) Cytokinin
(D) Gibberellin
Answer: (B) Ethylene
17. Which hormone is associated with stomatal closure during water stress?
(A) Abscisic acid
(B) Auxin
(C) Gibberellin
(D) Cytokinin
Answer: (A) Abscisic acid
18. Gibberellins are particularly associated with:
(A) Stem elongation and seed germination
(B) Blood clotting
(C) Closing stomata only
(D) Protein digestion
Answer: (A) Stem elongation and seed germination
Transport in Plants
19. Which tissue transports water and minerals from roots to the aerial parts of a plant?
(A) Phloem
(B) Xylem
(C) Cambium
(D) Epidermis
Answer: (B) Xylem
20. Which tissue transports sugars and other organic nutrients from leaves to other parts of the plant?
(A) Xylem
(B) Phloem
(C) Cortex
(D) Epidermis
Answer: (B) Phloem
21. Water moves upward through xylem mainly due to:
(A) Transpiration pull and cohesion
(B) Photosynthesis alone
(C) Gravity alone
(D) Respiration alone
Answer: (A) Transpiration pull and cohesion
22. Root hairs are important because they:
(A) Produce flowers
(B) Increase the surface area for water and mineral absorption
(C) Transport sugars to leaves
(D) Carry out pollination
Answer: (B) Increase the surface area for water and mineral absorption
Reproduction in Plants
23. The male reproductive part of a flower is the:
(A) Pistil
(B) Stamen
(C) Sepal
(D) Ovary
Answer: (B) Stamen
24. The female reproductive part of a flower is the:
(A) Stamen
(B) Anther
(C) Pistil/carpel
(D) Filament
Answer: (C) Pistil/carpel
25. Pollen grains are produced in the:
(A) Stigma
(B) Ovary
(C) Anther
(D) Ovule
Answer: (C) Anther
26. After fertilization, the ovule generally develops into a:
(A) Fruit
(B) Seed
(C) Leaf
(D) Root
Answer: (B) Seed
27. After fertilization, the ovary generally develops into a:
(A) Seed
(B) Fruit
(C) Pollen grain
(D) Stamen
Answer: (B) Fruit
Seed Germination
28. Which of the following is generally essential for seed germination?
(A) Water, oxygen and suitable temperature
(B) Carbon dioxide only
(C) Strong sunlight only
(D) Fertilizer only
Answer: (A) Water, oxygen and suitable temperature
29. During seed germination, the first structure to emerge from the seed is usually the:
(A) Plumule
(B) Radicle
(C) Flower
(D) Cotyledon
Answer: (B) Radicle
Explanation: The radicle develops into the primary root and usually emerges first.
30. Which hormone promotes seed germination by helping break seed dormancy in many plants?
(A) Gibberellin
(B) Abscisic acid
(C) Ethylene
(D) Cytokinin only
Answer: (A) Gibberellin
Must-Memorize Plant Biology
| Topic | Key Association |
|---|---|
| Photosynthesis | CO₂ + water + light → food + O₂ |
| Chlorophyll | Absorbs light energy |
| Oxygen released in photosynthesis | Mainly from water |
| Respiration | Releases energy from food |
| Aerobic respiration | Uses oxygen |
| Mitochondria | Major site of aerobic respiration |
| Transpiration | Loss of water vapour |
| Stomata | Gas exchange + transpiration |
| Guard cells | Control stomatal opening |
| Auxin | Cell elongation/phototropism |
| Gibberellin | Stem elongation/seed germination |
| Cytokinin | Cell division |
| Ethylene | Fruit ripening |
| Abscisic acid | Stomatal closure/dormancy |
| Xylem | Water + minerals |
| Phloem | Sugars/organic nutrients |
| Root hairs | Absorption |
| Stamen | Male reproductive part |
| Anther | Produces pollen |
| Pistil/Carpel | Female reproductive part |
| Ovary | Contains ovules; becomes fruit after fertilization |
| Ovule | Becomes seed after fertilization |
| Seed germination | Water + oxygen + suitable temperature |
| Radicle | Develops into root |
| Plumule | Develops into shoot |
High-Frequency Application Questions
Plant bends toward light → Auxin
Fruit ripening → Ethylene
Water transport → Xylem
Food transport → Phloem
Water loss from leaves → Transpiration
Stomatal opening/closing → Guard cells
Water absorption → Root hairs
Pollen production → Anther
Fruit formation → Ovary
Seed formation → Ovule
Seed dormancy/stomatal closure → Abscisic acid
Seed germination → Gibberellin