5.2 Phagocytosis

Question 1

Describe the first line of defence against disease

Answer 1

To form a physical or chemical barrier

Question 2

Describe and explain the process of phagocytosis

Answer 2

1) A phagocyte recognises the antigens on a pathogen
2) The cytoplasm of the phagocyte moves round the pathogen, engulfing it.
3) The pathogen is now contained in a vacuole or a vesicle in the cytoplasm of the phagocyte.
4) A lysosome fuses with the phagocytic vacuole and the LYSOZYMES break down with the pathogen
5) The phagocyte presents the pathogens antigens, it sticks the antigens on its surface to activate other immune system cells.