20 MCQs — Photosynthesis (with Answers)

      1. Photosynthesis primarily occurs in which part of the plant?

a) Roots

b) Stem

c) Leaves

d) Flower
Answer: c) Leaves 

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2. The pigment essential for photosynthesis is:

a) Hemoglobin

b) Anthocyanin

c) Chlorophyll

d) Carotene
Answer: c) Chlorophyll 

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3. The overall equation for photosynthesis can be written as:

a) O2 + H2O → CO2 + C6H12O6

b) 6CO2 + 6H2O → C6H12O6 + 6O2

c) CO2 + C6H12O6 → O2 + H2O

d) None of these
Answer: b) 6CO2 + 6H2O → C6H12O6 + 6O2 

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4. Which is not a raw material for photosynthesis?

a) Sunlight

b) Carbon dioxide

c) Oxygen

d) Water
Answer: c) Oxygen 

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5. The end product of photosynthesis is:

a) Oxygen

b) Glucose

c) ATP

d) Carbon dioxide
Answer: b) Glucose 

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6. The site of light-dependent reactions is:

a) Stroma

b) Mitochondria

c) Grana (Thylakoid membranes)

d) Cytosol
Answer: c) Grana (Thylakoid membranes) 

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7. Which of the following releases oxygen during photosynthesis?

a) Reduction of CO2

b) Photolysis of water

c) Formation of glucose

d) Calvin cycle
Answer: b) Photolysis of water 

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8. In the process of photosynthesis, carbon dioxide is:

a) Oxidised

b) Reduced

c) Hydrolysed

d) Combusted
Answer: b) Reduced 

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9. The first stable product of photosynthesis in C3 plants is:

a) Oxaloacetate

b) Malate

c) 3-Phosphoglyceric acid (PGA)

d) Pyruvate
Answer: c) 3-Phosphoglyceric acid (PGA) 

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10. Which of the following factors does not affect the rate of photosynthesis?

a) Light intensity

b) Temperature

c) CO2 concentration

d) Humidity
Answer: d) Humidity 

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11. The scientist who first demonstrated that oxygen is released in photosynthesis was:

a) Joseph Priestley

b) Jan Ingenhousz

c) Robin Hill

d) Julius von Sachs
Answer: b) Jan Ingenhousz 

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12. Stomata are mainly responsible for:

a) Transpiration

b) Gaseous exchange

c) Food transport

d) Water absorption
Answer: b) Gaseous exchange 

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13. Which experiment proves that sunlight is necessary for photosynthesis?

a) Half-leaf experiment

b) IAA bioassay

c) Tissue culture

d) Chromatography
Answer: a) Half-leaf experiment 

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14. Which component of sunlight is most effective for photosynthesis?

a) Blue and red light

b) Green light

c) Ultraviolet light

d) Infrared light
Answer: a) Blue and red light 

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15. What is the main function of light energy in photosynthesis?

a) To reduce CO2

b) To split water molecules

c) To oxidise glucose

d) To absorb heat only
Answer: b) To split water molecules 

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16. Where does the Calvin cycle take place?

a) Grana

b) Stroma

c) Cytoplasm

d) Nucleus
Answer: b) Stroma 

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17. The process of making ATP in the presence of sunlight is termed:

a) Glycolysis

b) Photophosphorylation

c) Respiration

d) Photorespiration
Answer: b) Photophosphorylation 

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18. The main product of light-independent reaction is:

a) Oxygen

b) Glucose

c) ATP

d) NADPH
Answer: b) Glucose 

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19. How is water utilized in photosynthesis?

a) Source of carbon

b) Source of electrons and protons

c) Source of oxygen only

d) Only for cooling
Answer: b) Source of electrons and protons 

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20. When the rate of respiration exceeds the rate of photosynthesis, the plant will:

a) Grow more vigorously

b) Continue to live but will not store food

c) Die instantly

d) Store more food
Answer: b) Continue to live but will not store food ​