The region of antibody that recognises the antigen is called :-

Options

A. Paratope
B. Epitope
C. `F_(c)-`part
D. Hapten

Answer

To answer the question, "The region of antibody that recognizes the antigen is called:", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Components of Antibodies**: Antibodies are Y-shaped molecules that play a crucial role in the immune response. They consist of different regions, including the variable region and the constant region.

2. **Identify the Key Terms**:
- **Paratope**: This is the specific part of the antibody that binds to the antigen.
- **Epitope**: This is the part of the antigen that is recognized by the antibody.
- **Fragment Crystallizable (Fc) Region**: This part of the antibody is involved in effector functions but does not bind to the antigen.
- **Hapten**: A small molecule that can elicit an immune response only when attached to a larger protein.

3. **Determine the Correct Answer**: The question specifically asks for the region of the antibody that recognizes the antigen. The paratope is the part of the antibody that binds to the epitope on the antigen. Therefore, the correct answer is **paratope**.

4. **Eliminate Incorrect Options**:
- **Epitope**: This is not part of the antibody; it is part of the antigen.
- **Fragment Crystallizable Part**: This does not recognize the antigen.
- **Hapten**: This is not a region of the antibody.

### Final Answer:
The region of antibody that recognizes the antigen is called **paratope**.

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