Lecture 64 Flashcards

1
Q

where is the signal peptide gradient during the process of peptide/protein hormone synthesis

A

Endoplasmic reticulum

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2
Q

The final outcome between the hormone and the target cell depends on what factors?

A
  • Hormone concentration
  • Receptor number
  • Affinity of hormone for receptor
  • Duration of exposure to hormone
  • Intracellular factors enzymes, cofactors (may help process)
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3
Q

Minimal concentration of hormone needed to elicit measurable response

A

Threshold response

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4
Q

what are 2 ways to express the dose-response relationship

A

Responsiveness (up/down) and Sensitivity (left/right)

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5
Q

Magnitude of response correlated with hormone concentration, what happens when concentration increases?

A

As concentration increases, response will increase then level off

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6
Q

the more receptors, what happens to the maximal response?

A

maximal response increases

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7
Q

________ is the term for a further increase in hormone will elicit no more response

A

Maximum response

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8
Q

________ may cause a decrease in responsiveness

A

caused by:
* decrease in number of target cells
* decrease in total receptors/cell
* decrese inconcentration of enzymes activated by hormone

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9
Q

the higher the affinity for a hormone, the (more/ less) likely to get a response

A

more

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10
Q

The concentration of hormone producing 50 percent of maximal response

A

Sensitivity

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11
Q

If more hormone required to get 50% response what happens to the sensitivity

A

decrease

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12
Q

The less hormone required = ________ to sensitivity

A

increases

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13
Q

Sensitivity can be changed in two ways List them.

A

changing number of receptors OR affinity of receptors

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14
Q

Decreasing sensitivity = ________ of receptors

A

down-regulation

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15
Q

Either number or affinity of receptors decreases even when __________

A

hormone concentrations high

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16
Q

Decreasing sensitivity is down-regulation of receptors causes what 3 things

A
  • decrease synthesis of new receptors
  • increase degradation of existing receptors
  • inactivate receptor
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17
Q

what down-regulates TRH receptors in anterior pituitary

A

T3

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18
Q

Increasing sensitivity = ________ of receptors

A

up-regulation

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19
Q

Increasing sensitivity = up-regulation of receptors. What are the 2 ways this can be achieved

A

Either number or affinity of receptors increases

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20
Q

Increasing sensitivity is an up-regulation of receptors what 3 things can this lead to

A

increase synthesis of new receptors, decrease degradation of existing, activate receptors

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21
Q

example of up-regulation: ________ increases its receptors in skeletal muscle and liver

A

GH

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22
Q

Hormone is recognized and binds to a membrane receptor and this forms a __________

A

hormone-receptor complex

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23
Q

Once the Hormone-receptor complex is formed, what can happen

A

EITHER coupled to a signal-generating mechanism OR must act as one itself

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24
Q

Once the generated signal (second messenger) is formed, it can affect what

A

intracellular process by altering activity OR concentration of functional or structural proteins

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25
Q

Receptor systems are located in which of 2 locations

A

Either on cell membrane (faster) or within the cell (slower; cytoplasm or nucleus)

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26
Q

what system is this? Classified according to membrane receptor structure OR second messenger system used (Usually a rapid response (minutes))

A

Classic cell membrane receptor system

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27
Q

what system is this? Doesn’t use second messenger system, but rather an enzyme system such as kinases (Usually a rapid response (minutes))

A

Catalytic cell membrane receptor systems

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28
Q

what receptor systems have a rapid response

A

Catalytic and Classic

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29
Q

what receptor systems have a slow

A

Intracellular

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30
Q

If a higher hormone concentration is required to reach 50% of the maximal response, what has happened to hormone sensitivity?

A

decreased

31
Q

Coupling molecules used in ALMOST ALL membrane receptor systems

A

G-proteins

32
Q

Heterotrimeric proteins has how many subunits

A

3

33
Q

Active or Inactive when GTP is bound

A

ACTIVE

34
Q

Active or Inactive when GDP is bound

A

INACTIVE

35
Q

T/F Heterotrimeric proteins can be either stimulatory or inhibitory

A

t

36
Q

G-proteins are linked to one of two second messenger systems, what are the 2 enzymes involved?

A

Adenylyl cyclase & Phospholipase C

37
Q

What are the secondary messengers of cell membrane receptor systems

A

cAMP & IP3/Ca2+/DAG

38
Q

pair the enzyme with the secondary messenger:
* Adenylyl cyclase
* Phospholipase C
* cAMP
* IP3/Ca2+/DAG

A
  • Adenylyl cyclase & cAMP
  • Phospholipase C & IP3/Ca2+/DAG
39
Q

Hormone binds receptor coupled by a G protein what happens next

A

GTP binds G protein and activates adenylyl cyclase

40
Q

after GTP binds G protein and activates adenylyl cyclase, what happens

A

cAMP produced and activates protein kinase A

41
Q

once cAMP produced and activates protein kinase A what happens next

A

Intracellular proteins phosphorylated by protein kinase A, causing physiologic actions

42
Q

Once Intracellular proteins phosphorylated by protein kinase A, causing physiologic actions. How does the system get shut down

A

Phosphodiesterase degrades cAMP, shutting down system

43
Q

List some examples of hormones using the adenylyl cyclase system

A
  • FSH
  • LH
  • ADH
  • TSH
  • Calcitonin
44
Q

what is the job of a kinase

A

phosphorylate

45
Q

Phospholipase C system: Hormone binds receptor coupled by a G protein what happens next

A

GTP binds G protein and activates phospholipase C

46
Q

Phospholipase C system: once GTP binds G protein and activates phospholipase C what happens next

A

Phospholipase C liberates diacylglycerol (DAG) and IP3 from PIP2

47
Q

Phospholipase C system After Phospholipase C liberates diacylglycerol (DAG) and IP3 from PIP2 what happens next

A

IP3 causes Ca2+ release from ER or SR stores

48
Q

Phospholipase C system: After IP3 causes Ca2+ release from ER or SR stores what happens

A

Ca2+ and DAG activate protein kinase C, which phosphorylates proteins

49
Q

List some hormones using the phospholipase C system

A
  • GnRH
  • Angiotensin 2
  • ADH
  • Oxytocine
50
Q

Catalytic receptors on cell surface associated with enzymes on ________ side

A

intracellular side

51
Q

Guanylyl cyclase enzyme: GTP to cGMP to what to phosphorylates proteins

A

cGMP-dependent kinase

52
Q

Atrial natriuretic peptide (ANP) and nitric oxide (NO) use what enzyme system

A

Guanylyl cyclase enzyme

53
Q

which hormone receptor is Protein kinase A associated with

A

Adenylyl cyclase system

54
Q

which hormone receptor is Protein kinase C associated with

A

Phospholipase C system

55
Q

which hormone receptor is cGMP kinase associated with

A

Guanylyl cyclase enzyme system

56
Q

Serine/threonine kinase enzymes: Use either protein kinase A or C, as well as ________ and mitogen-activated protein kinases (MAPK) tophosphorylate serine and threonine

A

Ca2+-calmodulin-dependent protein kinase (CaMK)

57
Q

Use either protein kinase A or C, aswell as Ca2+-calmodulin-dependentprotein kinase (CaMK) and mitogen-activated protein kinases (MAPK) to phosphorylate __________

A

serine and threonine

58
Q

Tyrosine kinase activity ________ the receptor itself

A

within

59
Q

Receptor tyrosine kinases has ________ domains

A

3

60
Q

what are the 3 domains of receptor tyrosine kinases

A
  • Extracellular domain for binding
  • Transmembrane domain
  • Intracellular domain- where tyrosine kinase activity occurs
61
Q

Receptor tyrosine kinases: When hormone binds, intracellular portion of receptor will _________

A

phosphorylates itself

62
Q

receptor tyrosine kinases: There is a monomer type and a _______ type

A

dimer

63
Q

Receptor tyrosine kinases: Describe a Monomer type

A

Receptor us going to dimerize after hormone binds- tyrosine kinase activated and phosphorylate tyrosine on itself

64
Q

Receptor tyrosine kinases: Describe a Dimer type

A

Receptor is already a dimer such as insulin or IGF

65
Q

Tyrosine kinase-associated receptors: Associate with other proteins that have tyrosine kinase activity such as ________ family of receptors

A

Janus kinase family (JAK)

66
Q

Catalytic receptor systems - tyrosine kinases: T/F Intracellular portion cannot phosphorylate itself

A

t

67
Q

Steroid hormones utilize what receptor system

A

Intracellular receptor systems

68
Q

Intracellular receptor system uses either _____ or _____ receptors

A

Use either cytosolic or nuclear receptors

69
Q

Steroids are lipid soluble meaning they can

A

diffuse across the membrane (from cholesterol)

70
Q

Intracellular receptor systems: Initiate DNA transcription and synthesis of new proteinsm, is this process slow or fast

A

SLOW, VERY SLOW

71
Q

DNA transcription and synthesis of new proteins: Steroid hormone diffuses across membrane and binds receptor in cytosol or nucleus, what happens next

A
  • Receptor undergoes conformational change
  • complex dimerizes and binds to steroid-responsive elements (SREs)
72
Q

what does SRE stand for? What is it?

A

steroid-responsive elements (SREs); Specific DNA sequences in target genes

73
Q

DNA transcription and synthesis of new proteins: After receptor undergoes conformational change, complex dimerizes and binds to steroid-responsive elements (SREs) what happens

A
  • Complex is now a transcription factor
  • mRNA transcribed
  • translation occurs
  • new proteins
  • physiologic action
74
Q

List some hormones that utilize intracellular receptor systems

A
  • Sex hormones
  • Aldosterone
  • Vitamin D