Which of the following is correct regarding electron transport system of respiration ?

Options

A. NADP is directly oxidised bye complex IV.
B. Complex V is a mobile electron carrier.
C. Complex IV cause the reduction molecular oxygen .
D. Complex II contains two copper centres .

Answer

To solve the question regarding the electron transport system of respiration, we will analyze each option provided and determine which statement is correct.

### Step-by-Step Solution:

1. **Understanding the Electron Transport Chain (ETC)**:
- The electron transport chain is a series of protein complexes located in the inner mitochondrial membrane.
- It functions to transfer electrons from NADH and FADH2 to molecular oxygen (O2), ultimately forming water (H2O).

2. **Analyzing Each Option**:
- **Option A**: "NADP is directly oxidized by complex IV."
- **Analysis**: NADP is not involved in the electron transport chain. Instead, NADH and FADH2 are the primary electron donors. Thus, this statement is incorrect.

- **Option B**: "Complex V is a mobile electron carrier."
- **Analysis**: Complex V (ATP synthase) is not an electron carrier; it synthesizes ATP using the proton gradient created by the electron transport chain. Therefore, this statement is also incorrect.

- **Option C**: "Complex IV causes the reduction of molecular oxygen."
- **Analysis**: Complex IV (cytochrome c oxidase) is responsible for the reduction of molecular oxygen to water. This statement is correct.

- **Option D**: "Complex II contains two copper centers."
- **Analysis**: Complex II (succinate dehydrogenase) does not contain copper centers; these are found in Complex IV. Thus, this statement is incorrect.

3. **Conclusion**:
- After analyzing all options, the only correct statement is **Option C**: "Complex IV causes the reduction of molecular oxygen."

### Final Answer:
The correct option regarding the electron transport system of respiration is **Option C**: "Complex IV causes the reduction of molecular oxygen."