Assertion(A): Immediately after light becomes unavailable, the biosynthetic process continues for some time, and then stops.
Reason(R): It is misnomer to call a biosynthetic phase a dark reaction.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.

Subtopic:  Dark Reaction: Biosynthetic Phase |
 61%
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Assertion(A): Melvin Calvin contributed to working out the complete biosynthetic pathway of photosynthesis.
Reason(R): He used radioactive 14C in bacterial photosynthesis.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Dark Reaction: Biosynthetic Phase |
 53%
From NCERT
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Assertion(A): RuBisCO has affinity for both the gases: CO2 and O2.
Reason(R): RuBisCO is the most abundant enzyme in the biosphere.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Light Reaction: Photophosphorylation |
 81%
From NCERT
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Assertion(A): C3 plants show a pathway called photorespiration.
Reason(R): RuBisCO binds with oxygen under specific conditions in C3 plants.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Photorespiration |
 76%
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Assertion(A): In C4 plants, photorespiration does not occur.
Reason(R): They have a mechanism that increases the concentration of CO2 at the enzyme site.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Question on C4 Pathway |
 91%
From NCERT
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Assertion(A): As a plant photosynthesises, many factors will simultaneously affect its rate.
Reason(R): Usually one factor is the major cause or is the one that limits the rate.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Factors Affecting Photosynthesis |
 62%
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Assertion(A): When several factors affect any [bio] chemical process, Blackman’s (1905) Law of Limiting Factors comes into effect.
Reason(R): At any point of photosynthesis, the rate will be determined by the factor available at sub-optimal levels.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Factors Affecting Photosynthesis |
From NCERT
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Assertion(A): The effect of water as a factor is more through its effect on the plant, rather than directly on photosynthesis.
Reason(R): Water stress also makes leaves wilt and increases metabolic activity as well.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Factors Affecting Photosynthesis |
 60%
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Assertion(A): It is only the green part of the plants that release oxygen.
Reason(R): Ingenhousz showed that in bright sunlight, small bubbles were formed around the green parts.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Historical View: Experiments |
From NCERT
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Assertion(A): The proton gradient across the thylakoid membrane is very important for photosynthesis.
Reason(R): The breakdown of this gradient leads to the synthesis of ATP.
Choices for Assertions and reasons:
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Dark Reaction : Calvin Cycle |
 86%
From NCERT
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