In which of the following only Ps I is found ?

Options

A. Stroma
B. Granal thylakoids
C. Stromal lamella
D. Matrix

Answer

To solve the question "In which of the following only PS I is found?", we will analyze the options provided and understand the context of Photosystem I (PS I).

### Step-by-Step Solution:

1. **Understand Photosystem I (PS I)**:
- PS I stands for Photosystem I, which is involved in the light reactions of photosynthesis.
- It is a protein complex located in the thylakoid membrane of chloroplasts and is crucial for the transfer of electrons during photosynthesis.

2. **Identify the Options**:
- The options given are:
1. Stroma
2. Granulothylakoids
3. Stromal lamellae
4. Matrix

3. **Analyze Each Option**:
- **Stroma**: This is the fluid-filled space surrounding the thylakoids in chloroplasts. Both PS I and PS II are present here.
- **Granulothylakoids**: These are stacks of thylakoids (grana) where both PS I and PS II are also present.
- **Stromal Lamellae**: This is the part of the thylakoid membrane that connects the grana. It is known to contain only PS I and not PS II.
- **Matrix**: This refers to the inner space of the chloroplast where both PS I and PS II are present.

4. **Conclusion**:
- From the analysis, the only structure where only PS I is found is the **Stromal Lamellae**.

### Final Answer:
**The correct answer is: Stromal Lamellae.**

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