In the dark reaction of photosynthesis , assimilatory power is used for the reduction of

Options

A. PGA
B. PGAL
C. RuBp
D. PEP

Answer

To solve the question regarding the dark reaction of photosynthesis and the use of assimilatory power, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Dark Reaction**: The dark reaction of photosynthesis is also known as the Calvin Cycle or C3 pathway. It occurs in the stroma of chloroplasts and does not require light directly.

2. **Identify the Role of Assimilatory Power**: In the context of photosynthesis, assimilatory power refers to the energy and reducing power generated during the light reactions. This includes ATP and NADPH, which are used in the dark reactions.

3. **Recognize the Key Substrates**: The main substrates involved in the dark reaction include:
- PGA (3-phosphoglycerate)
- PGAL (phosphoglyceraldehyde)
- RuBP (ribulose bisphosphate)
- PEP (phosphoenolpyruvate)

4. **Focus on the Reduction Process**: The reduction phase of the Calvin Cycle involves converting PGA into PGAL. This reduction is facilitated by the assimilatory power (ATP and NADPH) generated during the light reactions.

5. **Conclude the Correct Answer**: Since the question asks for what is reduced using assimilatory power in the dark reaction, the answer is PGA, which gets reduced to PGAL.

### Final Answer:
The assimilatory power is used for the reduction of **PGA (3-phosphoglycerate)**.

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