DCMU

Options

A. Inhibits PS-1
B. Inhibites PS-II
C. Destroys chloroplast
D. Inhibits oxidative phosphorylation

Answer

**Step-by-Step Solution:**

1. **Understanding DCMU**: DCMU stands for 3-(3,4-dichlorophenyl)-1,1-dimethylurea, also known as diuron. It is a chemical compound used primarily as a herbicide and in research to study photosynthesis.

2. **Function of DCMU**: DCMU specifically inhibits Photosystem II (PSII) in the photosynthetic process. It does this by blocking the electron transfer chain, particularly the transfer of electrons from plastoquinone to cytochrome b6f.

3. **Impact on Photosynthesis**: By inhibiting PSII, DCMU prevents the conversion of light energy into chemical energy, which is essential for the photosynthesis process. This inhibition leads to a reduction in the plant's ability to produce glucose and other organic compounds.

4. **Analyzing the Options**:
- **Option A**: Inhibits PS1 - This is incorrect as DCMU specifically inhibits PSII.
- **Option B**: Inhibits PS2 - This is the correct answer since DCMU blocks the function of Photosystem II.
- **Option C**: Destroys chloroplasts - This is incorrect; DCMU does not destroy chloroplasts.
- **Option D**: Inhibits oxidative phosphorylation - This is also incorrect; DCMU does not affect oxidative phosphorylation directly.

5. **Conclusion**: The correct answer to the question regarding the action of DCMU is that it inhibits Photosystem II (PS2).

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