Movement of `H^+` from lumen to stroma through the `F_0` portion of ATPase is

Options

A. According to concentration gradient
B. By simple diffusion
C. By active transport
D. Against conc . gradient

Answer

### Step-by-Step Solution:

1. **Understanding the Context**: The question is about the movement of hydrogen ions (H⁺) from the lumen of the thylakoid to the stroma of the chloroplast through the F₀ portion of ATP synthase (ATPase).

2. **Identifying the Mechanism**: The movement of H⁺ ions is driven by the proton motive force, which is created by the difference in concentration of protons across the thylakoid membrane.

3. **Concentration Gradient**: H⁺ ions move from an area of higher concentration (the lumen) to an area of lower concentration (the stroma). This movement occurs along the concentration gradient.

4. **Role of ATP Synthase**: The F₀ portion of ATP synthase acts as a channel for protons. As protons flow through this channel, they drive the synthesis of ATP from ADP and inorganic phosphate (Pi).

5. **Conclusion**: The correct answer to the question is that the movement of H⁺ from the lumen to the stroma through the F₀ portion of ATPase occurs **along the concentration gradient**.

### Final Answer:
The movement of H⁺ from lumen to stroma through the F₀ portion of ATPase is **along the concentration gradient**.

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