An antibody molecule is represented as `H_2L_2` This implies that

Options

A. each antibody has four antigen-binding sites.
B. each antibody molecule has four peptide chains , two small called light and two longer called heavy chains
C. there are 2 interchain disulphide bonds .
D. there are 2 intrachain disulphide bonds .

Answer

To solve the question regarding the representation of an antibody molecule as `H2L2`, we can break it down step by step.

### Step-by-Step Solution:

1. **Understanding Antibody Structure**:
- Antibodies are proteins produced by the immune system to identify and neutralize pathogens such as bacteria and viruses. They are also known as immunoglobulins.

2. **Components of Antibodies**:
- An antibody molecule is composed of four polypeptide chains: two heavy chains and two light chains. The heavy chains are longer, while the light chains are shorter.

3. **Representation of Antibody**:
- The notation `H2L2` indicates that there are:
- 2 heavy chains (denoted by `H2`)
- 2 light chains (denoted by `L2`)

4. **Total Number of Chains**:
- Since there are 2 heavy chains and 2 light chains, the total number of peptide chains in the antibody molecule is:
- 2 (heavy) + 2 (light) = 4 peptide chains.

5. **Binding Sites**:
- Each antibody has two antigen-binding sites, which are formed by the variable regions of the heavy and light chains. However, the representation `H2L2` does not directly indicate the number of binding sites.

6. **Conclusion**:
- The representation `H2L2` primarily informs us about the composition of the antibody in terms of its heavy and light chains, confirming that there are 4 peptide chains in total: 2 heavy chains and 2 light chains.

### Final Answer:
The representation `H2L2` implies that each antibody molecule consists of 2 heavy chains and 2 light chains, totaling 4 peptide chains.

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