PHYSL 212 > CELL 4 > Flashcards

CELL 4 Flashcards

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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
what is a protein kinase
enzyme that phosphorylates other proteins
26
what happens when protein is phosphorylated
1. change in conformation | 2. change in activity
27
what does change in protein activity produce
response in cell
28
G PROTEIN COUPLED RECEPTORS where are G proteins located
intracellular side of PM
29
G PROTEIN COUPLED RECEPTORS what can G proteins bind
1. GDP | 2. GTP
30
G PROTEIN COUPLED RECEPTORS what are 3 subunits of G protein
1. alpha 2. beta 3. gamma
31
G PROTEIN COUPLED RECEPTORS what is the function of G proteins
link bw G protein coupled receptor + effector protein
32
G PROTEIN COUPLED RECEPTORS what is effector protein
target that G protein affects activity of
33
G PROTEIN COUPLED RECEPTORS what are examples of effector proteins
1. ion channel | 2. enzyme
34
G PROTEIN COUPLED RECEPTORS what is the function of alpha subunit
bind GTP or GDP
35
G PROTEIN COUPLED RECEPTORS wha tis the function of beta and gamma subunits
anchor alpha subunit in mem
36
G PROTEIN COUPLED RECEPTORS what does G protein couple receptor have
binding site for messenger
37
G PROTEIN COUPLED RECEPTORS what does portion of receptor on cytosolic side bind to
G protein
38
G PROTEIN COUPLED RECEPTORS what is bound to G protein when there is no messenger bound to receptor
GDP
39
G PROTEIN COUPLED RECEPTORS what happens when messenger binds to receptor
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
G PROTEIN COUPLED RECEPTORS how does inactivation of alpha subunit occur
removes phosphate from GTP leaving GDP bound to alpha subunit
41
G PROTEIN COUPLED RECEPTORS what does alpha subunit do to effector protein
alter its activity to produce response in cell
42
G PROTEIN COUPLED RECEPTORS what happens when alpha subunit becomes inactivated
recombine w other 2 subunits
43
G PROTEIN COUPLED RECEPTORS why does G protein not stay activated for long
alpha subunit hydrolyzes GTP to GDP + Pi
44
G PROTEIN COUPLED RECEPTORS how does G protein affect ion channels
alters flow of ions through channel by a. opening channel b. closing channel
45
G PROTEIN COUPLED RECEPTORS what is stimulatory G protein
one that activates enzyme | - activate production of second messengers inside cell
46
G PROTEIN COUPLED RECEPTORS what is inhibitory G protein
one that inhibits enzyme | - inhibit production of second messengers
47
G PROTEIN COUPLED RECEPTORS what is the function of enzymes that G proteins target
catalyze production of second messengers inside cell
48
what does altering movement of ions ultimately alter
electrical properties of cell
49
what is effect of G protein on enzyme
stimulates or inhibits enzyme
50
when will GTP bound alpha subunit stimulate enzyme
if G protein is stimulatory
51
when will GTP bound alpha subunit inhibit enzyme
if G protein is inhibitory
52
what is the function of amplifier
catalyzes production of second messenger
53
what happens if enzyme activity stimulated
increase production of second messenger
54
what happens if enzyme activity inhibited
decrease production of second messenger
55
what are the steps of cAMP second messenger system
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 10. phosphorylated proteins alter activity causing cellular response 11. phosphodiesterase terminates cAMPY by converting cAMP to AMP
56
how can first messenger inhibit cAMP second messenger system
activating Gi protein
57
what happens if Gi protein activated in cAMP second messenger system
inhibit activity of adenylyl cyclase
58
what is second messenger in cAMP second messenger system
cAMP
59
what is conc of Ca in cyto
low
60
what is conc of Ca in ECF
high
61
what organelle stores Ca
ER
62
what happens when Ca channels in ER open
Ca moves from ER to cyto
63
what are steps of calcium calmodulin second messenger system
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
what are 2 possibilities for receptor in calcium calmodulin second messenger system
1. receptor is ligand gated ion channel | 2. receptor activates G protein
65
what happens if receptor activates G protein
1. first messenger binds to receptor 2. receptor activates G protein 3. activated G protein opens effector Ca channel
PHYSL 212
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