Immune Responses

Question 1

Process of phagocytosis

Answer 1

1. The phagocyte is attracted to the pathogen due to the chemical products produced by it
2. The phagocyte has several receptors on its membrane that attach to the chemicals on the pathogen
3. The phagocyte engulfs the pathogen leading to the formation of a phagosome
4. The lysosomes release their lysosymes into the phagosome, where they hydrolyse the bacterium
5. The hydrolysis products are absorbed by the phagocyte

Question 2

Physical defence mechanisms

Answer 2

1. Skin: acts as a tough barrier consisting of keratin
2. Stomach acid: kills bacteria
3. Gut and skin flora: natural bacterial flora competes with pathogens for food and space

Question 3

Non specific immune responses

Answer 3

1. Lysosome action
2. Phagocytosis
3. Inteferons: interferons prevent virus spreading to uninflected cells by stopping protein synthesis in viruses

Question 4

Specific immune responses

Answer 4

1. Cell mediated response
2. Humudol response