cell biology: plasma membrane Flashcards Preview

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Flashcards in cell biology: plasma membrane Deck (16):
1

contents of plasma membrane

phospholipids (very abundant)
sphingolipids (sphingomyelin)
glycolipids
glycoproteins
proteins (very abundant, transport proteins, tyrosine kinase receptor, G-protein linked receptor)
cholesterol (↑rigidity, ↑ melting temp)
ergosterol (if fungal membrane)

2

what are these:
phosphatidylCHOLINE
phosphatidylSERINE
phosphatidylINOSITOL (precursor of arachidonic acid)

phospholipids

3

location of following receptor types:
tyrosine kinase receptor
G-protein coupled receptor
steroid receptor

plasma membrane:
tyrosine kinase receptor (transmembrane)
G-protein coupled receptor (transmembrane)
cytoplasm:
steroid receptor: estrogen/testosterone enter cell

4

these are examples of what receptor type?
insulin receptor, IGF-1 R (2ß subunits have TK activity, 2α subunits bind extracellular ligand, bound by disulfide bonds= STRONG)
PDGF-R, GF R (SINGLE-pass transmembrane receptor)

tyrosine kinase receptor

5

mechanism of tyrosine kinase receptor

bind extracellular ligand → induces conformation change → induces autophosphorylation of tyrosine kinase (first step in signaling cascade) → can transfer phosphate form ATP to tyrosine side chains too

6

mechanism of Na-K ATPase

For each ATP consumed (on cytosol side) →3 Na+ OUT, 2 K+ IN
K+ inside cell maintains resting potential at -55 mV (need for neurotransmission, muscle contraction)
Na+ will slowly go down its natural gradient (out→in) → releases energy which drives molecules AGAINST their concentration gradient

7

drugs that inhibit Na-K ATPase →↑ Na+ in → heart beats harder

digoxin
digitoxin

8

drug that inhibits Na-K ATPase by binding to K+ site

ouabain

9

enzyme adds phosphate group to substrate using ATP

kinase

10

enzyme adds inorganic phosphate to substrate WITHOUT ATP

phosphorylase

11

enzyme removes phosphate from substrate

phosphatase

12

enzyme oxidizes substrate using electron acceptor

dehydrogenase

13

enzyme transfers carbon group with help of biotin (co-factor)

carboxylase

14

enzyme adds hydroxyl group to substrate

hydroxylase

15

enzyme relocates a functional group in a molecule

mutase

16

inherited disorder which causes mutated LDL receptor which can't bind adaptin + clathrin for receptor mediated endocytosis (no cholesterol stored in cells)

familial hypercholesterolemia
↑ risk MI

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