Simple diffusion does not require

Options

A. Concentration difference
B. Proteins
C. ATP
D. Both (B) & (C)

Answer

**Step-by-Step Solution:**

1. **Understanding Simple Diffusion**:
- Simple diffusion is a process where molecules move from an area of higher concentration to an area of lower concentration without the need for energy input.

2. **Identifying Requirements for Simple Diffusion**:
- It is essential to note that simple diffusion does not require any external energy, such as ATP, because it is a passive transport mechanism.

3. **Concentration Gradient**:
- For simple diffusion to occur, there must be a concentration gradient. This means there needs to be a difference in concentration between two areas. Molecules will naturally move from the area of higher concentration to the area of lower concentration until equilibrium is reached.

4. **Role of Proteins**:
- Unlike facilitated diffusion, which requires specific proteins (like carrier proteins) to help transport substances across the membrane, simple diffusion does not require any proteins. Molecules can pass directly through the lipid bilayer of the cell membrane if they are small and non-polar.

5. **Conclusion**:
- Therefore, simple diffusion does not require concentration difference (this is incorrect as it does), proteins (correct), or ATP (correct). The correct answer to the question is that simple diffusion does not require both proteins and ATP.

**Final Answer**: Simple diffusion does not require proteins and ATP (both B and C).

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