the haeme - protein complexes which act is oxidising agents are known as

Options

A. Haemoglobin
B. Myoglobin
C. Chlorophyll
D. Cytochrome.

Answer

To solve the question regarding the heme-protein complexes that act as oxidizing agents, we will analyze the given options step by step.

### Step 1: Understand the Question
The question asks for heme-protein complexes that serve as oxidizing agents. Heme proteins typically contain iron and are involved in various biological processes, including electron transfer.

**Hint:** Focus on the role of heme-proteins in oxidation-reduction reactions.

### Step 2: Evaluate Each Option
1. **Hemoglobin**:
- Hemoglobin is a protein found in red blood cells (RBCs) that primarily transports oxygen from the lungs to the tissues and carbon dioxide back to the lungs. It does not act as an oxidizing agent.
- **Conclusion**: This option is incorrect.

**Hint:** Consider the primary function of hemoglobin.

2. **Myoglobin**:
- Myoglobin is a muscle protein that stores oxygen in muscle tissues. Its main role is to facilitate oxygen diffusion within muscles, not to act as an oxidizing agent.
- **Conclusion**: This option is also incorrect.

**Hint:** Think about the location and function of myoglobin in muscle tissues.

3. **Chlorophyll**:
- Chlorophyll is a pigment found in plants that plays a crucial role in photosynthesis by capturing light energy. While it is involved in redox reactions during photosynthesis, it is not classified as a heme-protein complex that acts as an oxidizing agent.
- **Conclusion**: This option is incorrect.

**Hint:** Reflect on the role of chlorophyll in plants and its relation to photosynthesis.

4. **Cytochrome**:
- Cytochromes are heme-containing proteins that play a vital role in the electron transport chain (ETC). They facilitate electron transfer through oxidation and reduction reactions. The iron in cytochromes can exist in two states (ferrous and ferric), allowing them to act as oxidizing agents by accepting electrons.
- **Conclusion**: This option is correct.

**Hint:** Focus on the function of cytochromes in cellular respiration and ATP generation.

### Step 3: Final Answer
After evaluating all the options, the heme-protein complex that acts as an oxidizing agent is **cytochrome**.

**Final Answer:** Cytochrome (Option D)