ICSE Class 10

General instructions: Answer all questions. Marks are shown in brackets [ ].

Objective

1. 1.
   The individual flattened stacks of membranous structures inside the chloroplasts are known as:

   1. a. Grana
   2. b. Stroma
   3. c. Thylakoids
   4. d. Cristae
   [1]
2. 2.
   What are the disc-like structures of chloroplast in which chlorophyll is present called?

   1. A. Stroma
   2. B. Granum
   3. C. Thylakoid
   4. D. Lamella
   [1]
3. 3.
   Where are thylakoids located, and what is their primary function?

   1. A. In the mitochondria; ATP production.
   2. B. Inside chloroplasts as grana; trap sunlight and aid in photophosphorylation.
   3. C. In the cytoplasm; protein synthesis.
   4. D. In the nucleus; DNA replication.
   [1]
4. 4.
   257. Formation of ATP from ADP is termed as

   1. A. Photophosphorylation
   2. B. phosphorylation
   3. C. photolysis
   4. D. photosynthesis
   [1]
5. 5.
   What is the primary food product produced by plants during photosynthesis?

   1. A. Starch
   2. B. Glucose
   3. C. Cellulose
   4. D. Protein
   [1]
6. 6.
   178. Chloroplasts are the organelles in plant cells primarily associated with which of the following processes?

   1. A. Respiration
   2. B. Photosynthesis
   3. C. Digestion
   4. D. Protein synthesis
   [1]
7. 7.
   Glucose produced during photosynthesis is soon polymerised into starch. What does polymerisation mean in this context?

   1. A. The breakdown of starch into smaller glucose molecules for energy release.
   2. B. The process of combining several small glucose molecules to form a larger molecule of starch.
   3. C. The conversion of glucose into oxygen and water during respiration.
   4. D. The absorption of glucose by plant roots from the soil.
   [1]
8. 8.
   In the experimental setup shown (img-6.jpeg) to demonstrate oxygen evolution during photosynthesis, what is the role of the inverted test tube?

   1. A. To supply carbon dioxide to the plant.
   2. B. To collect and trap oxygen bubbles released by the plant.
   3. C. To provide water to the plant for photosynthesis.
   4. D. To prevent the escape of chlorophyll from the leaves.
   [1]
9. 9.
   A biologist studies how ADP is converted to ATP during photosynthesis under different light conditions. The process of conversion of ADP to ATP during Photosynthesis:

   1. a. Polymerisation.
   2. b. Photophosphorylation.
   3. c. Photorespiration.
   4. d. Photolysis.
   [1]
10. 10.
    Where are thylakoids located, and what is their primary function in a plant cell?

    1. A. Inside the chloroplast as piles forming grana; trap sunlight to initiate photosynthesis.
    2. B. In the cytoplasm; store starch and other nutrients.
    3. C. Within the mitochondria; produce ATP during respiration.
    4. D. On the leaf surface; regulate gas exchange through stomata.
    [1]
11. 11.
    What is the source of hydrogen ions in photosynthesis?

    1. a. Carbon dioxide
    2. b. Water
    3. c. Oxygen
    4. d. Chlorophyll
    [1]
12. 12.
    Which of the following sequences correctly represents the given food chain in logical order: Caterpillar, Snake, Owl, Frog, Green leaves?

    1. A. Green leaves → Caterpillar → Frog → Snake → Owl
    2. B. Green leaves → Frog → Caterpillar → Snake → Owl
    3. C. Caterpillar → Green leaves → Frog → Snake → Owl
    4. D. Green leaves → Snake → Caterpillar → Frog → Owl
    [1]
13. 13.
    Why is the right kidney positioned slightly lower than the left kidney in the human body?

    1. A. To accommodate the spleen on the left side.
    2. B. To adjust for the liver on the right side of the abdominal cavity.
    3. C. To balance the weight of the stomach.
    4. D. Due to the position of the descending aorta.
    [1]
14. 14.
    What happens in photolysis during the light-dependent reaction of photosynthesis?

    1. A. Water molecules are split into oxygen, protons, and electrons using light energy.
    2. B. Carbon dioxide is converted into glucose using light energy.
    3. C. Oxygen molecules combine with protons to form water.
    4. D. Light energy is stored directly in ATP without splitting water.
    [1]
15. 15.
    How do carbon dioxide and oxygen move into and out of a mesophyll cell?

    1. A. Active transport
    2. B. Diffusion
    3. C. Respiration
    4. D. Transpiration
    [1]
16. 16.
    Which of the following correctly represents the balanced chemical equation for photosynthesis along with the accurate explanation of its components?

    1. A. 6 CO₂ + 12 H₂O → C₆H₁₂O₆ + 6 H₂O + 6 O₂; Carbon dioxide and water produce glucose and oxygen using light energy and chlorophyll.
    2. B. 6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂; Carbon dioxide and water produce glucose and oxygen without requiring light energy.
    3. C. 12 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 H₂O + 6 O₂; Carbon dioxide and water produce glucose, water, and oxygen with chlorophyll but no light.
    4. D. 6 CO₂ + 12 H₂O → C₆H₁₂O₆ + 12 O₂; Carbon dioxide and water produce glucose and oxygen, releasing excess water vapor.
    [1]
17. 17.
    175. Arrange the following terms in the correct logical sequence for the light reaction of photosynthesis: 1. Water molecules 2. Oxygen 3. Grana 4. Hydrogen and hydroxyl ions 5. Photons

    1. A. 5, 3, 1, 4, 2
    2. B. 3, 5, 1, 2, 4
    3. C. 1, 5, 3, 4, 2
    4. D. 5, 1, 3, 4, 2
    [1]
18. 18.
    What happens during photorespiration?

    1. A. Uptake of oxygen and production of carbon dioxide
    2. B. Release of glucose
    3. C. Uptake of carbon dioxide and release of oxygen
    4. D. Absorption of chlorophyll
    [1]
19. 19.
    Why is it not possible to demonstrate respiration in a green plant kept in sunlight?

    1. A. Photosynthesis produces oxygen, masking the oxygen consumed during respiration, making respiration unmeasurable.
    2. B. Sunlight inhibits respiration, so the plant stops respiring entirely during the day.
    3. C. Respiration occurs only in darkness, so it cannot be observed in sunlight.
    4. D. The plant uses all available oxygen for photosynthesis, leaving none for respiration.
    [1]
20. 20.
    Which of the following sequences correctly represents the steps involved in the light phase of photosynthesis?

    1. A. 1. Chlorophyll absorbs photons → 2. Water splits into H⁺ and OH⁻ → 3. NADP forms NADPH → 4. Oxygen released → 5. ADP converts to ATP.
    2. B. 1. Chlorophyll absorbs photons → 2. CO₂ splits into carbon and oxygen → 3. NADP forms NADPH → 4. Oxygen released → 5. ADP converts to ATP.
    3. C. 1. Chlorophyll absorbs photons → 2. Water splits into H⁺ and OH⁻ → 3. ATP forms ADP → 4. Oxygen released → 5. NADP forms NADPH.
    4. D. 1. Chlorophyll absorbs photons → 2. Water splits into H⁺ and OH⁻ → 3. NADP forms NADPH → 4. Glucose formed → 5. ADP converts to ATP.
    [1]