Which of the following processes requires ATP ?

Options

A. Active process
B. Passive process
C. Both a and b
D. None of these

Answer

To determine which processes require ATP, we can break down the concepts of active and passive processes.

### Step-by-Step Solution:

1. **Understand Active Processes**:
- Active processes are those that move substances against their concentration gradient. This means that molecules move from an area of lower concentration to an area of higher concentration.
- Since this movement is against the natural flow, it requires energy.

2. **Role of ATP**:
- The energy required for active processes is provided by ATP (adenosine triphosphate). ATP is the primary energy currency of the cell, and it is utilized in various cellular processes that require energy input.

3. **Understand Passive Processes**:
- In contrast, passive processes involve the movement of substances along their concentration gradient, meaning they move from an area of higher concentration to an area of lower concentration.
- This movement does not require energy input from ATP, as it occurs naturally due to the concentration gradient.

4. **Conclusion**:
- Since active processes require energy to move substances against their concentration gradient, they require ATP. Passive processes do not require ATP as they follow the concentration gradient.

### Final Answer:
Active processes require ATP.

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