Question

Draw a labelled diagram showing the structure of an antibody molecule.

Hint:

The specific arrangement of the $H_2L_2$ structure is essential for the specificity of the immune response.

Answer 1

Step 1: Understanding the Concept:
Antibodies (immunoglobulins) are produced by B-lymphocytes in response to pathogens. They are made of four polypeptide chains.
Step 2: Detailed Explanation:
The labels for the antibody diagram include:
1. Heavy Chains: Two identical long polypeptide chains.
2. Light Chains: Two identical short polypeptide chains.
3. Disulphide Bonds: Bridges that hold the chains together.
4. Antigen-Binding Site: Located at the "variable" region at the tips of the 'Y' where the antibody attaches to a specific antigen.
5. Variable and Constant Regions: Parts of the chains that differ (variable) or remain similar (constant) between different antibodies.
Step 3: Final Answer:
The diagram depicts a $H_2L_2$ structure with two heavy and two light chains connected by disulphide linkages, featuring specific antigen-binding sites.