Topic 3 - inter-relationships: infectious diseases

Question 1

Name two animal vectors. What pathogens do they carry and what diseases do the pathogens cause?

Answer 1

E.g. the Anopheles mosquito carries the protozoan that causes malaria and the house fly carries the bacterium that causes dysentery.

Question 2

What physical barriers does the body have to stop pathogens entering?

Answer 2

E.g. the skin, cilia and mucus.

Question 3

How does the body use hydrochloric acid as a defence against pathogens?

Answer 3

If you eat food that contains pathogens, most of them will be killed by the hydrochloric acid in the stomach.

Question 4

Give six different ways pathogens can be spread.

Answer 4

E.g. In water, in food, in the air, by contact, in bodily fluids and by animal vectors.

Question 5

What chemical barriers does the body have to stop pathogens entering?

Answer 5

E.g. lysozyme in tears and hydrochloric acid in the stomach.