CELL 4 Flashcards

1
Q

what is signal transduction

A

sequence of events between binding of messenger to receptor and cellular response

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2
Q

what are chemical messengers

A
  1. form of indirect intercellular communication

2. ligand that binds reversibly to receptor

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3
Q

what does reversible binding mean

A

ligand + receptor can come together and come apart

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4
Q

what happens when one cell releases chemical messenger

A

binds to receptor on another cell

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5
Q

what does binding of chemical messenger to receptor result in

A

cellular response

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6
Q

what are 2 types of chemical messengers

A
  1. lipid soluble

2. lipid insoluble

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7
Q

what happens if messenger lipid soluble

A

can pass through PM to bind to intracellular receptor

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8
Q

what happens if messenger is lipid insoluble

A

cannot pass through PM to bind to intracellular receptor

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9
Q

where can receptors be located

A
  1. PM of cell (mem bound)
    2.cytoplasm (intracellular)
    3 nucleus (inracellular)
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10
Q

what do lipid soluble chemical messengers bind to

A
  1. mem bound receptors

2. intracellular receptors

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11
Q

what do lipid insoluble chemical messengers bind to

A

mem bound receptors

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12
Q

INTRACELLULAR RECEPTORS what is mechanism of lipid soluble messengers if receptor is in cyto

A
  1. diffuse from capillaries to interstitial fluid
  2. diffuse across PM
  3. messenger binds to receptor in cyto
  4. messenger-receptor complex moves into nucleus through nuclear pores
  5. messenger receptor complex functions as a transcription factor
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13
Q

INTRACELLULAR RECEPTORS what is the mechanism of lipid soluble messengers if receptor is in nucleus

A
  1. diffuse from capillaries to interstitial fluid
  2. diffuse across PM
  3. diffuse across nuclear mem
  4. binds to receptor in nucleus
  5. messenger receptor complex acts as transcription factor
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14
Q

MEM BOUND RECEPTORS what surface are of PM are mem bound receptors located on

A

extracellular

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15
Q

MEM BOUND RECEPTORS what are paracrine compounds

A

compounds released by one cell + act on neighbouring cell

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16
Q

MEM BOUND RECEPTORS what are autocrine compounds

A

compounds released by one cell + act on same cell

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17
Q

what is first messenger

A

extracellular messenger

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18
Q

what is second messenger

A
  1. molecule that enters cyto as a result of binding of first messenger
  2. molecule generated in cyto as a result of binding of first messenger
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19
Q

INTRACELLULAR RECEPTORS how do lipid soluble chemical messengers produce effect in cell

A

act as transcription factors

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20
Q

INTRACELLULAR RECEPTORS what is the function of transcription factors

A
  1. bind to response element (DNA sequence at beginning of gene)
  2. activate or deactivate gene
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21
Q

INTRACELLULAR RECEPTORS what does activation of gene mean

A

mRNA transcription

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22
Q

INTRACELLULAR RECEPTORS what does deactivation of gene mean

A

no mRNA transcription

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23
Q

INTRACELLULAR RECEPTORS what happens as a result of transcription being affected

A
  1. alter rate of translation

2. alter rate of protein synthesis

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24
Q

INTRACELLULAR RECEPTORS what does protein synthesis lead to

A

cellular response

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25
Q

what is a protein kinase

A

enzyme that phosphorylates other proteins

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26
Q

what happens when protein is phosphorylated

A
  1. change in conformation

2. change in activity

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27
Q

what does change in protein activity produce

A

response in cell

28
Q

G PROTEIN COUPLED RECEPTORS where are G proteins located

A

intracellular side of PM

29
Q

G PROTEIN COUPLED RECEPTORS what can G proteins bind

A
  1. GDP

2. GTP

30
Q

G PROTEIN COUPLED RECEPTORS what are 3 subunits of G protein

A
  1. alpha
  2. beta
  3. gamma
31
Q

G PROTEIN COUPLED RECEPTORS what is the function of G proteins

A

link bw G protein coupled receptor + effector protein

32
Q

G PROTEIN COUPLED RECEPTORS what is effector protein

A

target that G protein affects activity of

33
Q

G PROTEIN COUPLED RECEPTORS what are examples of effector proteins

A
  1. ion channel

2. enzyme

34
Q

G PROTEIN COUPLED RECEPTORS what is the function of alpha subunit

A

bind GTP or GDP

35
Q

G PROTEIN COUPLED RECEPTORS wha tis the function of beta and gamma subunits

A

anchor alpha subunit in mem

36
Q

G PROTEIN COUPLED RECEPTORS what does G protein couple receptor have

A

binding site for messenger

37
Q

G PROTEIN COUPLED RECEPTORS what does portion of receptor on cytosolic side bind to

A

G protein

38
Q

G PROTEIN COUPLED RECEPTORS what is bound to G protein when there is no messenger bound to receptor

A

GDP

39
Q

G PROTEIN COUPLED RECEPTORS what happens when messenger binds to receptor

A
  1. G protein changes conformation
  2. alpha subunit releases GDP
  3. alpha subunit binds GTP
  4. activated alpha subunit separates from beta and gamma subunit
  5. alpha subunit moves to effector protein
  • G protein activated
40
Q

G PROTEIN COUPLED RECEPTORS how does inactivation of alpha subunit occur

A

removes phosphate from GTP leaving GDP bound to alpha subunit

41
Q

G PROTEIN COUPLED RECEPTORS what does alpha subunit do to effector protein

A

alter its activity to produce response in cell

42
Q

G PROTEIN COUPLED RECEPTORS what happens when alpha subunit becomes inactivated

A

recombine w other 2 subunits

43
Q

G PROTEIN COUPLED RECEPTORS why does G protein not stay activated for long

A

alpha subunit hydrolyzes GTP to GDP + Pi

44
Q

G PROTEIN COUPLED RECEPTORS how does G protein affect ion channels

A

alters flow of ions through channel by

a. opening channel
b. closing channel

45
Q

G PROTEIN COUPLED RECEPTORS what is stimulatory G protein

A

one that activates enzyme

- activate production of second messengers inside cell

46
Q

G PROTEIN COUPLED RECEPTORS what is inhibitory G protein

A

one that inhibits enzyme

- inhibit production of second messengers

47
Q

G PROTEIN COUPLED RECEPTORS what is the function of enzymes that G proteins target

A

catalyze production of second messengers inside cell

48
Q

what does altering movement of ions ultimately alter

A

electrical properties of cell

49
Q

what is effect of G protein on enzyme

A

stimulates or inhibits enzyme

50
Q

when will GTP bound alpha subunit stimulate enzyme

A

if G protein is stimulatory

51
Q

when will GTP bound alpha subunit inhibit enzyme

A

if G protein is inhibitory

52
Q

what is the function of amplifier

A

catalyzes production of second messenger

53
Q

what happens if enzyme activity stimulated

A

increase production of second messenger

54
Q

what happens if enzyme activity inhibited

A

decrease production of second messenger

55
Q

what are the steps of cAMP second messenger system

A
  1. first messenger binds to receptor
  2. receptor undergoes conformational change
  3. GDP dissociated from alpha subunit
  4. GTP associates with alpha subunit
  5. activated alpha subunit dissociated from beta and gamma subunits
  6. activated alpha subunit moves to adenylyl cyclase
  7. catalytic site of adenylyl cyclase catalyzes conversion of cytosolic ATP to cAMP
  8. caMP binds to protein kinase A
    9 protein kinase A phosphorylates proteins
  9. phosphorylated proteins alter activity causing cellular response
  10. phosphodiesterase terminates cAMPY by converting cAMP to AMP
56
Q

how can first messenger inhibit cAMP second messenger system

A

activating Gi protein

57
Q

what happens if Gi protein activated in cAMP second messenger system

A

inhibit activity of adenylyl cyclase

58
Q

what is second messenger in cAMP second messenger system

A

cAMP

59
Q

what is conc of Ca in cyto

A

low

60
Q

what is conc of Ca in ECF

A

high

61
Q

what organelle stores Ca

A

ER

62
Q

what happens when Ca channels in ER open

A

Ca moves from ER to cyto

63
Q

what are steps of calcium calmodulin second messenger system

A
  1. first messenger binds to receptor in PM
  2. Ca moves into cell through Ca channels
  3. Ca binds to ion channel receptors on ER
  4. ion channel open
  5. Ca moves into cyto
  6. Ca binds to inactive calmodulin
  7. Ca-calmodulin complex activates calmodulin-dependent protein kinase
  8. kinase phosphorylates proteins in cell
  9. phosphorylated proteins alter activity causing response in cell
64
Q

what are 2 possibilities for receptor in calcium calmodulin second messenger system

A
  1. receptor is ligand gated ion channel

2. receptor activates G protein

65
Q

what happens if receptor activates G protein

A
  1. first messenger binds to receptor
  2. receptor activates G protein
  3. activated G protein opens effector Ca channel