Antigens binds to this part of antibody.

Options

A. Paratope
B. Epitope
C. FC fragment
D. Fab fragment

Answer

### Step-by-Step Solution:

1. **Understanding Antibodies**: Antibodies are proteins produced by the immune system to identify and neutralize pathogens such as bacteria and viruses.

2. **Identifying the Components of Antibodies**: Antibodies consist of different parts, including the Fab fragment and Fc fragment. The Fab fragment is responsible for binding to antigens.

3. **Defining Key Terms**:
- **Peritope**: This is the specific part of the antibody that binds to an antigen. It is also known as the antigen-binding site.
- **Epitope**: This is the specific part of the antigen that is recognized and bound by the peritope of the antibody.
- **Fc Fragment**: This part of the antibody does not bind to antigens but is involved in other immune functions.

4. **Identifying the Correct Answer**: From the options given (peritope, epitope, Fc fragment, and Fab fragment), the correct answer is **peritope**. This is because the peritope is the region on the antibody that directly interacts with the antigen.

5. **Understanding the Structure**: The peritope is a small region located in the variable part of the antibody and is composed of approximately 15 to 22 amino acids.

6. **Conclusion**: The peritope is crucial for the formation of the antigen-antibody complex, which is essential for the immune response.

### Final Answer:
Antigens bind to the **peritope** part of the antibody.

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