ATP ase activity occur in :

Options

A. Head of `F_(1)`–particle
B. Stalk of `F_(1)`–particle
C. Base of `F_(1)`–particle
D. All the above

Answer

To determine where ATPase activity occurs, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding ATPase**: ATPase is an enzyme that catalyzes the hydrolysis of ATP, releasing energy that can be used for various cellular processes.

2. **Identifying the Context**: The question specifies "F1 particle," which is part of ATP synthase, an enzyme complex found in the mitochondria.

3. **Structure of ATP Synthase**: ATP synthase consists of two main parts:
- The **F0** portion, which is embedded in the mitochondrial membrane.
- The **F1** portion, which protrudes into the mitochondrial matrix and is responsible for ATP synthesis.

4. **Regions of the F1 Particle**: The F1 particle is divided into three regions:
- **Head**: This is the part where ATP synthesis occurs.
- **Stalk**: Connects the head to the base.
- **Base**: Anchors the complex to the membrane.

5. **Locating ATPase Activity**: The ATPase activity specifically occurs in the **head** of the F1 particle. This is where ATP is synthesized from ADP and inorganic phosphate (Pi) during cellular respiration.

6. **Evaluating Options**: The options provided are:
- Head of the F1 particle
- Stalk of the F1 particle
- Base of the F1 particle
- All of the above

Based on the information, the correct answer is **the head of the F1 particle**.

### Final Answer:
**ATPase activity occurs in the head of the F1 particle.**

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