The region that contains the binding and catalytic sites is termend as

Options

A. active site
B. apoenzyme
C. holoenzyme
D. allosteric site

Answer

To solve the question, "The region that contains the binding and catalytic sites is termed as," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question is asking for the specific term that describes a region in an enzyme where two important functions occur: binding of the substrate and catalysis of the reaction.

2. **Identify the Options**: The options provided are:
- A) Active site
- B) Apoenzyme
- C) Holoenzyme
- D) Allosteric site

3. **Define Each Option**:
- **Active Site**: This is the specific region of an enzyme where substrate molecules bind and undergo a chemical reaction. It includes both the binding site and the catalytic site.
- **Apoenzyme**: This refers to the protein part of an enzyme without its cofactor. It is inactive on its own.
- **Holoenzyme**: This is the complete enzyme that includes the apoenzyme and its cofactor, making it active.
- **Allosteric Site**: This is a site on the enzyme where molecules can bind, but it is not the active site. Binding here can change the enzyme's activity.

4. **Analyze the Definitions**: The active site is the only option that encompasses both the binding and catalytic functions of the enzyme.

5. **Select the Correct Answer**: Based on the definitions and analysis, the correct answer is:
- **A) Active site**

### Final Answer:
The region that contains the binding and catalytic sites is termed as the **active site**.

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