Choose correct option w.r.t. anaerobic respiration

Options

A. The first oxidation step occurs in mitochondria
B. All reactions occur in the cytoplasm
C. They require oxygen only at one step
D. First step of reaction occur in cytoplasm then in mitochondria

Answer

To solve the question regarding anaerobic respiration, let's analyze each option step by step:

1. **Understanding Anaerobic Respiration**:
- Anaerobic respiration is a type of respiration that occurs in the absence of oxygen. It primarily includes processes like lactic acid fermentation and alcoholic fermentation.

2. **Evaluating Option A**:
- **Statement**: "The first oxidation step occurs in mitochondria."
- **Analysis**: This statement is incorrect because anaerobic respiration does not take place in the mitochondria. Instead, it occurs in the cytoplasm. Mitochondria are involved in aerobic respiration, which requires oxygen.

3. **Evaluating Option B**:
- **Statement**: "All reactions occur in the cytoplasm."
- **Analysis**: This statement is correct. Both lactic acid fermentation and alcoholic fermentation, which are types of anaerobic respiration, occur entirely in the cytoplasm.

4. **Evaluating Option C**:
- **Statement**: "They require oxygen only at one step."
- **Analysis**: This statement is incorrect. Anaerobic respiration does not require oxygen at any step. The first step, glycolysis, occurs in the absence of oxygen.

5. **Evaluating Option D**:
- **Statement**: "First step of reaction occurs in cytoplasm then in mitochondria."
- **Analysis**: This statement is also incorrect. All steps of anaerobic respiration occur in the cytoplasm, and there is no transition to the mitochondria.

6. **Conclusion**:
- The only correct option with respect to anaerobic respiration is **Option B: All reactions occur in the cytoplasm**.

### Final Answer:
The correct option is **B: All reactions occur in the cytoplasm**.