lecture 22 - transport across cell membranes Flashcards Preview

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Flashcards in lecture 22 - transport across cell membranes Deck (42)
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31

Na/K ATPase important for

- maintaining resting membrane potential
- electrical excitability
- muscle contraction
- maintain cell volume
- uptake of nutrients via secondary active transport
- pH by secondary active transport

32

Pump-leak hypothesis

Na and K are constantly leaking back in, thus the pump must work consistently

33

Na+ antiporters (or exchanges)

Na+ rushes in causing Ca2+ or H+ to be pushed out

34

Na+ symporters (or cotransporters)

glucose or amino acids (MUST BIND FIRST) then rush inwards together with Na+

35

endocytosis

large particles into the cell. Substance transported is inside a vesicle and therefore doesn't make contact with the hydrophobic core and whatnot

36

phagocytosis

cell eating - foreign particle binds to receptor proteins. pseudopods extend to form phagosome

37

pinocytosis

cell drinking - no receptor proteins, no pseudopods form, non-selective

38

exocytosis

substances are exported from cells by fusion of vesicle with cell membrane

39

vesicles necessary to...

prevent things from reacting that shouldn't be e.g. protease in the pancreas

40

neurotransmitters and enzymes transported via

exocytosis

41

receptor-mediated endocytosis for?

uptake of specific substances or LIGANDS

42

receptor-mediated endocytosis steps

1. desired substance binds receptor protein in CLATHERIN-COATED PIT REGION of membrane
2. causes membrane to fold inwards, forms vesicle
3. vesicles become uncoated and bind with ENDOSOME
4. receptor proteins seperate from ligands and return to surface
5. ligands digested by lysosomes or transported across cell