Where does dark reaction of photosynthesis take place?

Options

A. 1.Thylakoid lumen
B. 2.Thylakoid membrane
C. 3.Stroma of the chloroplast
D. 4.Matrix of mitochondria

Answer

To determine where the dark reaction of photosynthesis takes place, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Photosynthesis**:
- Photosynthesis consists of two main stages: the light reactions and the dark reactions (Calvin cycle). The light reactions occur in the thylakoid membranes of the chloroplasts, while the dark reactions utilize the products of the light reactions.

2. **Identifying the Location of Dark Reactions**:
- The dark reactions, also known as the Calvin cycle, do not require light directly. They take place in the stroma of the chloroplasts, which is the fluid-filled space surrounding the thylakoids.

3. **Evaluating the Options**:
- **Thylakoid lumen**: This is where the light reactions occur, making this option incorrect for dark reactions.
- **Thylakoid membrane**: This is also involved in the light reactions, thus not the correct answer.
- **Stroma of the chloroplast**: This is where the dark reactions occur, making this the correct answer.
- **Matrix of mitochondria**: This is involved in cellular respiration, not photosynthesis, so this option is also incorrect.

4. **Conclusion**:
- Based on the analysis, the dark reaction of photosynthesis takes place in the **stroma of the chloroplast**.

### Final Answer:
The dark reaction of photosynthesis takes place in the **stroma of the chloroplast**.

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