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BIO 107 - Cell and Mol. Bio > Cell Signaling Part 1 > Flashcards

Cell Signaling Part 1 Flashcards

1
Q

allows bacteria to coordinate their behavior, including their motility, antibiotic production, spore formation, and sexual conjugation

A

Quorom sensing

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2
Q

signals cells of the opposite mating type to stop proliferating and prepare to mate.

A

Mating factor in yeast

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3
Q

Intracellular signaling pathway

A

Extracellular signal molecule -> receptor protein -> Intracelullar signaling molecules -> effector proteins

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4
Q
  • Where reception of the signals depends on
  • at the cell surface, which bind the signal molecules
A

Receptor protein

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5
Q

Results after the binding of the receptor

A

intracellular signaling pathways or system

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6
Q

process the signal inside the receiving cell.

distribute them to appropriate intracelullar targets

A

Intracellular signaling proteins

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7
Q

small chemical messenger which carry the signal to other signaling proteins

A

Second messengers

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8
Q

the targets that lie at the end of signaling pathways

A

effector proteins

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9
Q

Four forms of intercellular signaling

A
  • Contact-dependent
  • paracrine
  • synaptic
  • endocrine
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10
Q

requires cells to be in direct membrane- membrane contact

A

Contact-dependent signaling

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11
Q

depends on local mediators that are released into the extracellular space and act on neighboring cells.

A

Paracrine signaling

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12
Q

is performed by neurons that transmit signals electrically along their axons and release neurotransmitters at chemical synapses, which are often located far away from the neuronal cell body

A

Synaptic signaling

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13
Q

depends on endocrine cells, which secrete hormones into the bloodstream for distribution throughout the body

A

Endocrine signaling

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14
Q

cells produce signals that they themselves respond to

A

Autocrine signaling

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15
Q

neurons; chemical
synapses

A

synaptic

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16
Q

high specificity of binding site of receptors

A

Target cell

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17
Q

extracellular signal molecule

A

ligand

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18
Q

cell responds to the signals ___

A

selectively

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19
Q

a signal molecule often has ___ ___ on different types of target cells

A

different effects

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20
Q

Acetylcholine effect in heart pacemaker cells

A

decreases the rate of action potential firing

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21
Q

Acetylcholine effects in salivary gland cells

A

stimulates the production of salive

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22
Q

Acetylcholine effets in skeletal muscle

A

causes the cells to contract

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23
Q

Cell surface receptors act as __ __

A

signal transducers

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24
Q

Three major classes of cell-surface receptor proteins

A
  • Ion-channel-coupled receptors
  • G-protein coupled receptors
  • Enzyme-coupled receptors
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25
Q
  • rapid synaptic signaling between nerve cells and other electrically excitable cells
  • transmitter-gated ion channels or ionotrophic receptors
  • electrically excitable cells
A
  • Ion-channel-coupled receptors
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26
Q
  • act by indirectly regulating the activity of a separate plasma-membrane-bound target protein (enzyme or ion channel)
A
  • G-protein coupled receptors
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27
Q

mediates the interaction between the activated receptor and this target protein

A

heterotrimeric GTP-binding protein

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28
Q

function as enzymes or associated directly with enzymes

A
  • Enzyme-coupled receptors
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29
Q

covalently adds one or more phosphate groups to specific amino acids on the signaling protein

A

Protein kinase

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30
Q

removes the phosphate groups

A

protein phosphate

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31
Q

Two Types of interacellular signaling proteins that act as molecular switches

A
  • Signaling by Phosphorylation
  • Signaling by GTP binding
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32
Q

Signaling by phosphorylation

A
  • A protein kinase covalently adds phosphate from ATP to signaling protein
  • A protein phosphate removes the phosphate
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33
Q

Signaling by GTP binding

A
  • GTP binding protein was induced to echcnage GDP to GTP
  • Activates the protein
  • The protein then inactivates itself by hydrolizing GTP to GDP
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34
Q

When GTP is bound it is an ___

A

on state

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35
Q

When GDP is bound it is an

36
Q

removes the phosphate
group

A

Phosphatases

37
Q
  • drive the proteins into an “off” state by increasing the rate of hydrolysis of bound GTP

(off; hydrolysis of GTP)

A

GTPase-activating proteins (GAPS)

38
Q

activate GTP-binding proteins by promoting the release of bound GDP

on; release bound GDP

A

Guanin nucleotide exchange factors (GEFs)

39
Q

bring together groups of interacting signaling proteins into signaling complexes, often before a signal has been received

A

Scaffold proteins

40
Q

Types of intracellular signaling complexes

A

A. REFORMED SIGNALING COMPLEX ON A SCAFFOLD PROTEIN

B. ASSEMBLY OF SIGNALING COMPLEX ON AN ACTIVATED RECEPTOR

C. ASSEMBLY OF SIGNALING COMPLEX ON PHOSPHOINOSITIDE DOCKING SITES

41
Q

Give the basic signaling properties that vary in different system

A
  1. Response
  2. Sensitivity
  3. Dynamic range
  4. persistence
  5. Signal processing
  6. integration
  7. coordination
42
Q

timing varies dramatically in different signaling systems

43
Q

is often controlled by changes in the number or affinity of the receptors on the
target cell

  • number or affinity; amplification
A

Sensitivity

44
Q

tend to act at very low concentrations on their distant target cells

  • High sensitivity to low concentration of signal
45
Q

operate at much higher concentrations at a synapse, reducing the need for high sensitivity in postsynaptic receptors

A

Neurotransmitters

46
Q

A particularly important mechanism for increasing sensitivity

A

signal amplification

47
Q
  • the responsiveness. closely related to sensitivity
  • some systems are responsive over narrow range of extracellular signals
  • some are highly responsive over a much broader range of signal
A

Dynamic range

48
Q

response can be transient or prolonged/permanent response

A

Persistence

49
Q

allows a response to be governed by multiple inputs.

A

Integration

50
Q

Types of abrupt responses

A
  • Sigmoidal response
  • Discontinous or all-or-none response
51
Q

smoothly graded response

A

Hyperbolic

52
Q

response rises steeply and continuously at intermediate stimulus levels

  • concentration rises beyond some threshold value
53
Q

the response switches on completely (and often irreversibly) when the signal reaches some threshold concentration

A

Discontinous or all-or-none response

54
Q

the output of a process acts back to regulate that same process

A

Feedback loops

55
Q

output stimulates its own production

A

positive feedback

56
Q

output inhibits its own production

A

Negative feedback

57
Q

prolonged exposure to a stimulus decreases the cell’s response to that level of stimulus

A

Adaptation or desensitization

58
Q
  • largest family of cell-surface receptors
  • a single polypeptide chain that threads back and forth across the lipid bilayer seven times, forming a cylindrical structure
  • G-proteins to relay the signal
A

G-protein-coupled receptors (GPCRs)

59
Q

What senses does GPCRs operate?

A
  • Sight
  • Smell
  • Taste
60
Q

Three protein subunits that G proteins are composed of

A

α, β, and γ

61
Q

is synthesized from ATP by an enzyme called adenylyl cyclase

A

Cyclic AMP

62
Q

breaks down cyclic AMP

A

cyclic AMP phosphodiesterases

63
Q

stimulatory G protein activates adenylyl cyclase

64
Q

stimulatory G protein inhibits adenylyl cyclase

65
Q

ADP ribosylation that alters the Gs α subunit- inactive

A

cholera toxin

66
Q

ADP ribosylation of the α subunit of Gi

A

petussis toxin

67
Q

phosphorylates specific serines or threonines, regulating their activity

A

cyclic-AMP dependent protein kinase

68
Q

cAMP activates the gene that encodes this hormone

A

somatostatin

69
Q

CRE-binding (CREB) protein

A

transcription regulator

70
Q

stimulates the transcription of the target genes

can transform a short cAMP signal into long-term change in a cell

A

CREB-binding protein (CBP)

71
Q

G-proteins that activate the plasma-membrane bound enzyme

A

phospholipase C-β (PLCβ)

72
Q

is a water-soluble molecule that leaves the plasma membrane and diffuses through the cytosol to the endoplasmic reticulum

73
Q
  • increases concentration of Ca2+ in the cytosol
A

IP3-gated Ca2+-release channels (IP3 receptors)

Binding of IP3 and Ca2+ into the IP3 receptors

74
Q

activates a monomeric GTPase (Rho family) which regulates the actin cytoskeleton

A

G protein called G12

75
Q

noncolor vision in dim light

A

rod photoreceptors (rods)

76
Q

color vision in bright light

A

cone photoreceptors (cones)

77
Q

stack of discs; contains cyclic-GMP-gated cation
channels

A

Phototransduction apparatus

78
Q

decreases the cyclic GMP conc. and closes the cation channel

A

Light - hyperpolarization

79
Q

hydrophobic, small, readily pass across the plasma membrane

A

Nitric Oxide (NO)

80
Q

Stimulates NO synthesis

A

Acetylcholine

81
Q

GPCRs 3 modes of adaptation

A
  1. receptor sequestration
  2. receptor down-regulation
  3. receptor inactivation
82
Q

they become altered so that they can no longer interact with G proteins

A

Receptor inactivation

83
Q

they are temporarily moved to the interior of the cell so that they no longer have access to their ligand

A

Receptor sequestration

84
Q

they are destroyed in lysosomes after internalization

A

Receptor destruction

85
Q

Where does desensitization of the GPCRs depends on?

A

Their Phosphorylation by PKA, PKC or a member of the family of GPCR kinases

BIO 107 - Cell and Mol. Bio (10 decks)

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