Topic 2C - Year 1 - Cells and the Immune System - Antigens

Question 1

What are antigens?

Answer 1

Antigens are proteins that can generate an immune response when detected by the body.

Question 2

Where are antigens found?

Answer 2

Antigens are usually found on all cell surfaces , you have antigens on your own body cells just as foreign cells have antibodies on their cell surfaces.

Question 3

What are antigens that arn’t normally found in the body referred to as?

Answer 3

Foreign Antigens

Question 4

What do antigens allow the immune system to identify?

Answer 4

Antigens allow the immune system to identify

• Pathogens
• Abnormal body cells
• Toxins
• Cells from other individuals of the same species (non-self cells)

Question 5

What is a pathogen?

Answer 5

A pathogen is an organism that causes disease.

Question 6

What do pathogens carry on their surface which triggers the immune response?

Answer 6

Foreign antigens

Question 7

What is meant by an abnormal body cell?

Answer 7

A cancerous or pathogen infected cell is an abnormal body cell.

Question 8

What do abnormal body cells carry on their surface to trigger an immune response?

Answer 8

Foreign antigens

Question 9

What is a toxin?

Answer 9

A toxin’s are poisons. A toxin is a molecule and not a cell.

Question 10

Where do toxins come from?

Answer 10

Often bacteria produce toxins.

Question 11

Sometimes an organ is rejected by the body after a transplant procedure , why is this?

Answer 11

When you receive cells from someone else your body may notice that the antigens on the cell surface are forging as even though the organ will have come from one of your own species its antigens may differ from your own , the foreign antigens trigger an immune response which leads to rejection of the transplanted organ.