[5.1-2] defence mechanisms and phagocytosis Flashcards

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1
Q

what will proteins embedded in the cell membrane act as a mechanism for?

A
  • identifying cells as ‘self’, rather than ‘non-self’
  • this is the basis of the immune response (recognition system)
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2
Q

how does the immune system recognise the proteins?

A

because they have a specific tertiary structure

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3
Q

what is an immune response triggered by?

A

the presence of a ‘non-self material’ eg.

  1. pathogens (bacteria, viruses)
  2. human cells from another individual
  3. tumour cells
  4. toxic molecules from pathogens
  • these will all be covered in proteins that will act as ‘non-antigens’
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4
Q

what is the 5 step process of phagocytosis?

A
  1. bacteria engulfed due to membrane fluidity of phospholipid bilayer
  2. bacterium now contained in a ‘phagosome’
  3. lysosomes fuse with phagosome to form a ‘phagolysosome’
  4. therefore, lysozymes can hydrolyse bacterial molecules
  5. the hydrolysis products of the bacterium are absorbed by the phagocyte
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5
Q

what are some examples of products of bacterial digestion?

A
  • amino acids
  • nucleic acids
  • monosaccharides
  • fatty acids / glycerol

BUT bacterial antigens are often retained intact by the phagocyte

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6
Q

what is an antigen?

A

any part of an organism or substance that is recognised as non-self (foreign) by the immune system and stimulates an immune response

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