Non-cyclic photophosphorylationdiffers from cyclic photophosphorylation in that the latter has

Options

A. Only `PS` I
B. Evolution of oxygen
C. Reduction of `NADP^(+)`
D. Both B and C.

Answer

### Step-by-Step Solution:

1. **Understand the Concepts**:
- Non-cyclic photophosphorylation and cyclic photophosphorylation are two processes involved in the light reactions of photosynthesis.
- Both processes involve the synthesis of ATP, but they differ in their mechanisms and products.

2. **Identify the Key Differences**:
- **Photosystems Involved**:
- **Cyclic Photophosphorylation**: Involves only Photosystem I (PSI).
- **Non-Cyclic Photophosphorylation**: Involves both Photosystem I (PSI) and Photosystem II (PSII).

- **Reaction Centers**:
- **Cyclic Photophosphorylation**: The reaction center is P700 (associated with PSI).
- **Non-Cyclic Photophosphorylation**: The reaction center is P680 (associated with PSII).

- **Products Synthesized**:
- **Cyclic Photophosphorylation**: Only ATP is synthesized.
- **Non-Cyclic Photophosphorylation**: Both ATP and NADPH are synthesized.

- **Oxygen Evolution**:
- **Cyclic Photophosphorylation**: Does not involve the photolysis of water; hence, oxygen is not released.
- **Non-Cyclic Photophosphorylation**: Involves the photolysis of water, resulting in the release of oxygen.

3. **Analyze the Question**:
- The question asks how non-cyclic photophosphorylation differs from cyclic photophosphorylation, specifically what is present in cyclic photophosphorylation.

4. **Select the Correct Answer**:
- From the differences identified, the correct answer is that cyclic photophosphorylation involves only Photosystem I (PSI).
- Therefore, the correct option is: **Only Photosystem I is involved in cyclic photophosphorylation**.