Describe the basic structure of an antibody.

Antibodies are Y-shaped glycoproteins produced by plasma cells.

What is the function of the variable region of an antibody?

The variable region is complementary to a specific antigen, allowing the antibody to bind to that antigen.

What is the constant region of an antibody?

The constant region is the same in all antibodies of the same class and determines the antibody's function.

How many polypeptide chains make up an antibody, and what are they called?

Antibodies consist of four polypeptide chains: two heavy chains and two light chains.

How do antibodies acting as opsonins enhance the immune response?

Antibodies acting as opsonins bind to pathogens and enhance phagocytosis by marking them for destruction by phagocytes.

What are agglutinins and how do they help eliminate pathogens?

Agglutinins are antibodies that cause pathogens to clump together, preventing them from entering cells and making them easier for phagocytes to engulf.

OCR A-Level Biology H420

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Communicable Diseases, Disease Prevention and the Immune System

Antibodies

1 thing to know
Components 02 and 03

Overview

The four polypeptide chains and the variable and constant regions, and how antibodies act as opsonins, agglutinins and anti-toxins.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

How do antibodies help eliminate pathogens?

Questions from this subtopic

Each one with the model answer underneath.

1
Describe the basic structure of an antibody.
Model answer
Antibodies are Y-shaped glycoproteins produced by plasma cells.
2
What is the function of the variable region of an antibody?
Model answer
The variable region is complementary to a specific antigen, allowing the antibody to bind to that antigen.
3
What is the constant region of an antibody?
Model answer
The constant region is the same in all antibodies of the same class and determines the antibody's function.
4
How many polypeptide chains make up an antibody, and what are they called?
Model answer
Antibodies consist of four polypeptide chains: two heavy chains and two light chains.
5
How do antibodies acting as opsonins enhance the immune response?
Model answer
Antibodies acting as opsonins bind to pathogens and enhance phagocytosis by marking them for destruction by phagocytes.
6
What are agglutinins and how do they help eliminate pathogens?
Model answer
Agglutinins are antibodies that cause pathogens to clump together, preventing them from entering cells and making them easier for phagocytes to engulf.

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