Phosphorylation during photosynthesis is

Options

A. Oxidative phosphorylation and photophosphorylation occurring in light and dark conditions.
B. Oxidative phosphorylation occurs in light conditions and photophosphorylation occurs in dark conditions.
C. Oxidative phosphorylation occurs in dark conditions and photophosphorylation occurs in light conditions.
D. Oxidative phosphorylation occurs in light and dark conditions and photophosphorylation occurs only in the presence of light.

Answer

To solve the question "Phosphorylation during photosynthesis is", we need to understand the types of phosphorylation that occur in the process of photosynthesis and their conditions.

### Step-by-Step Solution:

1. **Identify the Types of Phosphorylation**:
- There are two main types of phosphorylation relevant to photosynthesis: **Oxidative Phosphorylation** and **Photophosphorylation**.

2. **Understand Oxidative Phosphorylation**:
- This process occurs in the **mitochondria** of eukaryotic cells.
- It involves the reduction of oxygen to water, utilizing electrons donated by NADH and FADH2.
- Oxidative phosphorylation can occur in both **light and dark conditions**.

3. **Understand Photophosphorylation**:
- This process occurs in the **chloroplasts** during photosynthesis.
- It involves the oxidation of water to produce oxygen, with NADP+ acting as the electron acceptor.
- Photophosphorylation only occurs in the **presence of light**.

4. **Analyze the Options**:
- We need to determine which of the provided options correctly describes the conditions under which phosphorylation occurs during photosynthesis.
- The correct statement is that **oxidative phosphorylation occurs in both light and dark**, while **photophosphorylation occurs only in light**.

5. **Select the Correct Option**:
- Based on the analysis, the correct answer is **Option D**: "Oxidative phosphorylation occurs in light and dark conditions, and photophosphorylation occurs only in the presence of light."

### Final Answer:
The correct answer is **Option D**.

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