UNIT 2 (topic 4) non-specific immunity

Question 1

define a pathogen

Answer 1

a micro-organism that causes disease

Question 2

define an antigen

Answer 2

a protein detected as non-self that stimulates an immune response

Question 3

define an antibody

Answer 3

a protein produced by lymphocytes in response to a non-self antigen

Question 4

define the immune system

Answer 4

a system of biological structures and processes that identifies and kills pathogens

Question 5

how does skin protect against pathogens

Answer 5

covers most of the body to prevent the entry of pathogens

Question 6

how do tears protect against pathogens

Answer 6

lysosomes in tears hydrolyse pathogens that enter the eye

Question 7

how does stomach acid protect against pathogens

Answer 7

kills bacteria that enters the stomach by denaturing the proteins

Question 8

how does cilia and mucus protect against pathogens

Answer 8

become trapped in the mucus and cilia wafts the pathogen away from the lungs

Question 9

explain the steps of phagocytosis

Answer 9

• chemoattractant of the pathogen attract phagocyte
• phagocyte attaches to antigens on the surface
• cytoplasm surrounds the pathogen (engulfed) forming a phagosome
• lysosomes migrate to the phagosome and release digestive enzymes
• pathogen becomes hydrolysed