Define antibody. Using an appropriately labeled diagram, describe the structure of an antibody monomer. Indicate and label variable and constant regions, heavy and light chains.

Verified step by step guidance

1. Step 1: Define an antibody as a protein produced by the immune system to identify and neutralize foreign objects like bacteria and viruses.
2. Step 2: Describe the basic structure of an antibody monomer, which is Y-shaped and consists of four polypeptide chains: two identical heavy chains and two identical light chains.
3. Step 3: Explain that each chain has a constant region and a variable region. The variable regions are located at the tips of the 'Y' and are responsible for antigen binding.
4. Step 4: Indicate that the constant regions form the stem of the 'Y' and are involved in effector functions, such as binding to cell receptors or complement proteins.
5. Step 5: Suggest using a diagram to label the heavy chains, light chains, variable regions, and constant regions, ensuring clarity in the representation of the antibody structure.

Key Concepts

Antibody Definition

An antibody, also known as an immunoglobulin, is a specialized protein produced by B cells in response to antigens. Antibodies play a crucial role in the immune system by identifying and neutralizing foreign objects like bacteria and viruses. Each antibody is specific to a particular antigen, allowing for targeted immune responses.

Antibody Structure

An antibody monomer typically consists of four polypeptide chains: two heavy chains and two light chains, forming a Y-shaped structure. The arms of the Y contain the variable regions, which are responsible for binding to specific antigens, while the stem of the Y contains the constant region, which determines the antibody's class and effector functions.

Variable and Constant Regions

The variable regions of an antibody are located at the tips of the Y-shaped structure and are unique to each antibody, allowing for the specific recognition of different antigens. In contrast, the constant regions are the same across antibodies of the same class and are involved in mediating the immune response, such as recruiting other immune cells or activating complement pathways.