KANDPAL Q's [Intro: Signal Transduction] & [GPCR, Enzyme Linked Receptors, and Human Cancers] Flashcards

1
Q

signal transduction

A

communication bw environment and cell/between 2 cells

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2
Q

T/F signal output depends on extracellular signal molecules, and molecules that respond to signals

A

TRUE

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3
Q

4 types of signal transduction

A
  • contact-dependnent (development/immune response)
  • paracrine (neighboring cells)
  • synaptic (specific target)
  • endocrine (whole organism)
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4
Q

autocrine signaling:

signals secreted by the cell bind to self to reinforce _____, particularly during _____.

A

developmental decisions; differentiation

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5
Q

the _____ of the receptors by signal molecules determines the behavior of the cells.

A

differential occupancy

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6
Q

effect of acetylcholine on a heart muscle cell

A

decreased rate and force of contraction

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7
Q

effect of acetylcholine on a skeletal muscle cell

A

contraction

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8
Q

effect of acetylcholine on a salivary gland cell

A

secretion

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9
Q

acetylcholine receptor on cardiac muscle

A

G-protein coupled receptor

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10
Q

acetylcholine receptor on skeletal muscle

A

ligand gated Na+ channel

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11
Q

acetylcholine receptor on salivary gland

A

G-protein coupled receptor

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12
Q

what is different bw the acetylcholine receptors on the cardiac muscle and on the salivary gland?

A

intracellular signaling proteins

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13
Q

T/F most signal molecules are hydrophilic

A

TRUE

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14
Q

what is the physiological consequence of acetylcholine?

A

smooth muscle relaxation

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15
Q

acetyl choline effects are mediated indirectly by _____ of NO synthase and formation of _____

A

activation; nitric oxide (NO)

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16
Q

eNOS

A

NOS in endothelial cells

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17
Q

nNOS

A

NOS in nerve cells

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18
Q

_____ make iNOS

A

macrophages

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19
Q

are iNOS inducible?

A

yes

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20
Q

when are iNOS made?

A

only in response to infection

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21
Q

phosphodiesterase (PDE)

A

converts cyclic nucleotide into nucleotide monophosphate

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22
Q

where is PDE3 expressed?

A

in cardiac cells

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23
Q

where is PDE5 expressed?

A

in expandable erectile tissue

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24
Q

where is PDE6 expressed?

A

in retina

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25
Q

inhibition of PDE will lead to _____ of cyclic nucleotides

A

accumulation

26
Q

dynamite is an explosion of _____

A

prone nitroglycerine

27
Q

name the 6 hydrophobic signals mentioned in class

A
cortisol
estradiol
testosterone
vitamin D3
thyroxine
retinoic acid
28
Q

nitric oxide, a ____ molecule that readily passes throughout the membrane, mediates a variety of cellular changes that have been targeted by drugs used to treat _____ and _____.

A

small
angina
erectile dysfunction

29
Q

what synthesizes NO?

A

NOS

30
Q

T/F NOS, which synthesizes NO, also exists as various isoenzymes in tissues

A

TRUE

31
Q

soem signals result in a response within seconds to minutes and others take minutes to hours depending on _____ or _____

A

modification of existing proteins OR synthesis of new proteins

32
Q

nuclear receptors that recognize steroid hormone have a _____ and a _____

A

DNA binding domain AND ligand binding domain

33
Q

G-Protein Coupled Receptor (GPCR) = _____ + _____

A

Receptor + G-Protein

34
Q

how many transmembrane domains do GPCR have?

A

7

35
Q

what are the ligands for GPCR?

A
  • hormones
  • NTs (proteins, peptides, aa derivatives, fatty acids)
  • photon
  • H+
  • Ca2+
36
Q

what are the 2 similar structures that all GPCRs have?

A

seven pass & serpentine receptors

37
Q

N-terminus of GPCR is _____, whereas C-terminus is _____

A

extracellular; intracellular

38
Q

what do GPCR bind?

A

heterotrimeric G-proteins

39
Q

a G-protein is activated by disassembly of _____, _____, and _____

A

alpha, beta, gamma

40
Q

which part of the G-protein is the GTPase?

A

alpha

41
Q

_____ alpha of the G-proteinactivates its target proteins

A

active

42
Q

_____ bound alpha of G-protein is active

A

GTP

43
Q

what controls the activity of alpha subunit of G-protien?

A

RGS (Regulator of G-protein Signaling) proteins

44
Q

RGS proteins act as alpha subunit specific ____

A

GAPs (GTPase Activator Proteins)

45
Q

heterotrimeric G-proteins are classified into 4 categories based on their _____

A

downstream effects

46
Q

Gs

A
  • stimulatory G-protein

- active alpha subunit (GTP bound) activates adenylyl cyclase

47
Q

Gi

A
  • inhibitory G-protein

- active alpha subunit (GTP bound) inhibits adenylyl cyclase

48
Q

Gq

A

modulate phospholipase C (PLC) activity

49
Q

G12/13

A

involved in cytoskeleton reorganization and oncogenesis

50
Q

what does cAMP do?

A

activates protein kinase A (PKA)

51
Q

cAMP can also bind to certain channels for their activation. For example, _____, which is a _____ channel

A

CFTR (cystic fibrosis transmembrane conductance regulator); chloride channel

52
Q

what are the 2 subunits of PKA?

A

regulatory subunit and inactive catalytic subunit

53
Q

cAMP binds to which subunit of PKA?

A

regulatory subunit

54
Q

T/F phosphatidylinositol 4,5 bihosphate (PIP2) is found in inner half of plasma membrane

A

TRUE

55
Q

what converts PIP2 into IP3?

A

PLC-beta (phospholipase C-beta)

56
Q

cholera toxin

A

it modifies the alpha subunit of Gs-protein. by ADP-ribosylating the GTP bound alpha of the Gs-protein, the alpha remains active. as a consequence, adenylate cyclase is active. cAMP level rise. CFTR remains continuously activated. efflux of Cl- and water into the gut. diarrhea and vomiting

57
Q

what does pertusis toxin (whooping cough) do?

A

it modifies GDP-bound alpha subunit of Gi-protein. modified alpha can’t be activated by exchange of GDP for GTP. alpha remains inactive. Gi can’t do its job so adenylate cyclase cannot be inhibited. levels of cAMP remain elevated. CFTR activated.

58
Q

what is the fastest G-protein mediated responses known in vertebrates?

A

visual transduction

59
Q

visual transduction: receptor activation leads to fall in _____ levels

A

cGMP

60
Q

cGMP gated _____ channels open in (light/dark?) when cGMP levels are high

A

Na+; dark

61
Q

_____ activated rhodopsin activates _____ that in turn activates _____. this results in low cGMP level. Na + channels close. synaptic signaling inhibited as a result.

A

light; transducer (Gt); cGMP phosphodiesterase