Question

The following statements support the ‘Dark reaction’ in photosynthesis: A. Dark phase of photosynthesis is CO\textsubscript{2} fixation
B. Dark Phase is temperature sensitive
C. Dark reactions don't require light
D. Also called as Dark man reaction

• A. A, B and C only
• B. A, B and D only
• C. A, B, C and D
• D. B, C and D only

Hint:

Dark reaction = Calvin cycle = CO\textsubscript{2} fixation. Needs ATP + NADPH, but no direct light.

Answer 1

The Correct Option is A

Step 1: Recall the definition of dark reaction.
Dark reaction, also known as the Calvin cycle, is the set of reactions in photosynthesis that do not directly require light. Instead, they utilize ATP and NADPH produced in the light reaction to fix CO\textsubscript{2} into carbohydrates.
Step 2: Check each statement.
- A: CO\textsubscript{2} fixation occurs in the dark reaction → Correct.
- B: Temperature-sensitive since it involves enzyme-mediated reactions (Rubisco and others) → Correct.
- C: Do not require light directly, though dependent on products of light reactions → Correct.
- D: The phrase “Dark man reaction” is incorrect. It is often mistakenly written, correct term is Calvin cycle → Wrong.
Step 3: Conclusion.
Therefore, correct statements are A, B and C only.