Each immunoglobin has two heavy chains & two light chains, the antigen binding site is present in

Options

A. variable region of light chain
B. variable region of heavy chain
C. variable region of both heavy and light chain
D. constant region of both light and heavy chain

Answer

To answer the question regarding where the antigen binding sites are located in immunoglobulins, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Immunoglobulins**:
- Immunoglobulins, also known as antibodies, have a characteristic Y-shaped structure. Each immunoglobulin consists of two heavy chains and two light chains.

2. **Identify the Components**:
- The heavy chains are the longer chains of the Y shape, while the light chains are the shorter ones. Each chain has two distinct regions: the variable region and the constant region.

3. **Define Variable and Constant Regions**:
- The **variable region** is the part of the antibody that varies between different antibodies and is responsible for binding to specific antigens.
- The **constant region** is the part that remains the same among different antibodies and is involved in the effector functions of the antibody.

4. **Locate the Antigen Binding Sites**:
- The antigen binding sites are specifically located in the variable regions of both the heavy chains and the light chains. This is where the antibody interacts with the antigen.

5. **Conclusion**:
- Therefore, the correct answer to the question is that the antigen binding sites are present in the **variable regions of both the light and heavy chains**.

### Final Answer:
The antigen binding site is present in the variable region of both light and heavy chains.

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