Sections 5 - Immunity

Question 1

If a pathogen gets into the body, what type of white blood cell detects it?

Answer 1

Phagocyte

Question 2

What are antigens?

Answer 2

The molecules on the surface of the pathogens that the phagocytes detect

Question 3

Why don’t phagocytes detect our own antigens?

Answer 3

Phagocytes can tell the difference between ‘self’ and ‘foreign’ antigens

Question 4

What do phagocytes do?

Answer 4

Detect pathogens and engulf them, hence destroying them

Question 5

What type of white blood cells produce antibodies that bind to antigens?

Answer 5

B-lymphocytes

Question 6

What happens when B-cells bind to pathogens?

Answer 6

When the antibody binds to the antigen it brings about the death of the pathogen carrying it

Question 7

What are T-lymphocytes and what do they do?

Answer 7

T-cells (or T-lymphocytes) are a type of white blood cell that are involved in communication between phagocytes and B-cells. When a phagocyte has engulfed a pathogen it signals to the T-cell that it’s found something. The T-cell then activates the B-cells to produce antibodies.

Question 8

What do vaccines do?

Answer 8

• Vaccinations against a pathogen give you the ability to respond rapidly to an infection by that pathogen (immunity).
• Vaccines contain antigens from a pathogen in a form that can’t harm you, e.g. attached to dead bacteria.
• Your body produces antibodies against the antigens so, if the same pathogen (carrying the same antigens) tries to invade again, the immune system can respond really quickly and you’re less likely to suffer from any symptoms.