Phagocytosis

Question 1

Describe the process of phagocytosis

Answer 1

• Phagocyte is attracted to the pathogen due to chemical products released by it
• Phagocyte receptors attach to chemicals on pathogen’s surface and it is engulfed to form phagosome
• Lysosomes migrate towards phagosome and fuse with it
• Lysosomes release lysozymes to hydrolyse bacterium and its products are absorbed
• Some WBCs present antigens on their surface to activate other parts of the immune system

Question 2

Describe now bacteria are destroyed by phagocytes.

Answer 2

• Phagocyte engulfs bacteria to form a phagosome
• Lysosome empties contents into phagosome
• This releases lysozymes, which hydrolyse bacteria

Question 3

Give two structures a bacterial cell may have that a white blood cell
does not nave.

Answer 3

• Cell wall;
• Capsule / slime layer;
• Circular DNA
• Naked DNA / DNA without histones;
• acellum
• Plasmid

Question 4

When a pathogen enters the body it may be destroyed by phagocytosis.
Describe how

Answer 4

• Phagocyte attracted by chemicals produced by the pathogen
• (Pathogen) engulfed / ingested;
• Enclosed in a phagosome
• Phagosome fuses with lysosome,
• Lysosome contains lysozymes
• Pathogen digested / molecules hydrolysed;