Phagocytosis

Question 1

What do phagocytes do

Answer 1

Ingest and destroy the pathogen by a process called phagocytosis before it Can cause harm

Question 2

Describe phagocytosis

Answer 2

A phagocyte recognises the foreign antigens on a pathogen

Engulfs pathogen. Pathogen is in the phagosome

Lysosome containing hydrolytic enzymes fuse with phagosome, breaking down the pathogen

The phagosome fuses with cell membrane and released broken down pathogen out of cell

Antigen presentation occurs on phagocyte cell membrane

Question 3

Lysozymes are found in tears. Suggest a reason why

Answer 3

The protective covering of the eye, and especially the tear ducts, are potential entry points for pathogens. The eyes are vulnerable to infection because the coverings are thin to allow the light through. Lysozymes will break down the cell walls of any bacterial pathogens and so destroy them before they can cause harm