Which of the following acts as electron carrier in both photosynthesis and respirtion ?

Options

A. Ferredoxin
B. Phytochrome
C. Cytochrome
D. Cryptochrome

Answer

To determine which of the following acts as an electron carrier in both photosynthesis and respiration, we will analyze each option provided.

### Step-by-Step Solution:

1. **Identify the Options**: The question presents several options. We need to evaluate each one to see if it functions as an electron carrier in both processes.

2. **Evaluate Ferredoxin**:
- Ferredoxin is a protein found in chloroplasts that plays a crucial role in the electron transport chain during photosynthesis.
- However, it does not participate in respiration.
- **Conclusion**: Ferredoxin is not the correct answer.

3. **Evaluate Phytochromes and Cryptochromes**:
- Both phytochromes and cryptochromes are types of photoreceptors that respond to light.
- They are involved in various plant processes but do not function as electron carriers in either photosynthesis or respiration.
- **Conclusion**: Both options are incorrect.

4. **Evaluate Cytochrome**:
- Cytochromes are proteins that contain heme groups and are found in both the thylakoid membranes of chloroplasts (in photosynthesis) and the inner mitochondrial membrane (in respiration).
- They play a significant role in electron transport chains in both processes, facilitating oxidation and reduction reactions.
- Cytochromes are organized within membranes, allowing for efficient electron transfer.
- **Conclusion**: Cytochrome is the correct answer as it acts as an electron carrier in both photosynthesis and respiration.

5. **Final Answer**: The correct answer is **Cytochrome**.