Quiz 6.4-51.4 Flashcards

1
Q

where are ion channel linked receptors found?

A

found in the plasma membrane

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2
Q

what do ion channel linked receptors do?

A

convert chemical signals into electrical signals

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3
Q

what causes ion channel linked receptors to open or close?

A

the response to the binding of the signaling molecule (ligand)

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4
Q

what is an example of an ion channel linked receptor?

A

acetylcholine binding to and opening a ligand gated sodium ion channel

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5
Q

what are G-protein-linked receptors?

A

transmembrane proteins with an outside binding site for a signaling molecules, and an internal binding site for a specific G protein

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6
Q

what is the relationship between G-protein-linked receptors and transduction pathways?

A

couple signaling molecules transduction pathways in the cell

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7
Q

why are G-protein-linked receptors possibly important to the medical world?

A

more than 400 are potential targets for pharmaceutical interventions

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8
Q

what are enzyme-linked receptors?

A

transmembrane proteins with a binding site for a signaling molecules outside the cell and an enzyme component inside the cell

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9
Q

what do enzyme-linked receptors do?

A

bind hormones such as insulin and growth factors

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10
Q

what is the enzyme-linked receptor tyrosine kinase?

A

an enzyme that catalyzes transfer of phosphate groups (phosphorylation) from ATP to a specific tyrosine that is part of a protein

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11
Q

where are intracellular receptors located?

A

the cytosol or nucleus

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12
Q

what are most intracellular receptors?

A

transcript factors like the estrogen receptor (ER) that binds estrogen and is involved in some breast cancers

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13
Q

what is the relationship between intracellular receptors and membranes?

A

signaling molecules diffuse across the membrane of target cells

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14
Q

what ways do intracellular receptors diffuse across the membrane?

A

by combining with receptors in the cytosol and moving to the nucleus or binding to receptors already bound to DNA inside the nucleus

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15
Q

what is the first step of signal transduction?

A

regulatory molecules activate membrane proteins, which then transduce the signal

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16
Q

what is the second step to signal transduction?

A

a signaling molecule binds with a cell-surface receptor and activates it by changing the shape of the receptor tail which extends into cytoplasm

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17
Q

what is the third step to signal transduction?

A

a signal is relayed through protein kinases, creating a signaling pathway that amplifies the signal

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18
Q

how do signaling molecules acts as molecular switches?

A

each component in a signaling pathway can be active (on) or inactive (off)

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19
Q

what are molecular switches regulated by?

A

phosphorylation/dephosphrylation

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20
Q

how does protein kinase regulate molecular switches?

A

adding phosphate to typically activate a target

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21
Q

how does protein phosphatase regulate molecular switches?

A

catalyzes the removal of a phosphate group

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22
Q

when do closed ion channel gates open?

A

when a ligand binds to the receptor

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23
Q

what do GABA receptors bind to?

A

neurotransmitter GABA

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24
Q

what are GABA receptors?

A

ligand gated chloride ion channels

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25
Q

what does GABA do when chloride enters the cell?

A

inhibits neural signaling which inhibits transmission of neural impulses

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26
Q

what do G protein linked receptors initiate?

A

signal transduction

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27
Q

what inactive the G protein subunit is linked to?

A

guanosine diphosphate (GDP)

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28
Q

what replaced GDP when a signaling molecules binds to the receptor?

A

guanosine triphosphate (GTP)

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29
Q

what does GTP release?

A

energy

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30
Q

what are second messengers?

A

intracellular signaling agents

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31
Q

what is the first messenger and how does it relate to the second messenger?

A

the signaling molecule is the first messenger and information is relayed by the G protein to a second messenger

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32
Q

what does the second messenger do?

A

amplify signals inside the cell and relay to other signaling/target proteins

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33
Q

when receptors are activated how do they affect second messengers?

A

second messengers are produced in large quantities

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34
Q

what is the last molecule in the signaling chain and what does it do?

A

the second messenger, activates the final response

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35
Q

what is cyclic AMP?

A

a second messenger

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36
Q

what does adenylyl cyclase do?

A

convert ATP to cyclic AMP

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37
Q

what do some G proteins use as second messengers?

A

phospholipid components

38
Q

what does phophoplipase (PIP) split into?

A

IP3 or DAG

39
Q

what are calcium ions used for?

A

neural signals

40
Q

how do calcium ions work?

A

by binding to certain proteins which then activate certain enzymes

41
Q

How does calmodulin regulate calcium?

A

helps to regulate metabolism, muscle contraction, memory, inflammation, and apoptosis

42
Q

what are many activated intracellular receptors called?

A

transcription factors

43
Q

what do transcription factors do?

A

regulate gene expression

44
Q

for transcription factors, what does the binding of a ligand receptor complex to a specific region of DNA do?

A

activate/repress specific genes

45
Q

Activated genes produce?

A

messenger RNA

46
Q

what dies messenger RNA carry?

A

the code for synthesis of a particular proteins into the cytoplasm

47
Q

what are the three types of cellular response?

A

ion channels open/close, enzymes activity is altered, and specific gene activity turned on/off

48
Q

how does one signaling molecule create a cascade?

A

by leading changes in millions of molecules at the end of a signaling cascade

49
Q

what must happen to signals in the end?

A

they must be returned to their inactive state

50
Q

what are some things found in signaling pathways of most organisms?

A

G proteins, protein kinase, and phosphates

51
Q

how are some bacteria similar to eukaryotes?

A

they contains similar signal transduction pathways

52
Q

where did cell communication first evolve?

A

unicellular organisms

53
Q

what does development include?

A

all the changes that take place in an individual during its life, from fertilization until death

54
Q

how is an embryo formed?

A

the zygote divides by mitosis

55
Q

in animals, how does growth occur?

A

by the increase in the number of cells (mitosis)

56
Q

what contributes to the development of form?

A

cell determination, cell differentiation, pattern formation, and morphogenesis

57
Q

what happens in cell differentiation?

A

certain cells become biochemical and structurally specialized to carry out specific functions

58
Q

cell differential is the result of?

A

cell determination

59
Q

what is cell determination?

A

activities of certain genes are altered to progressively commit a cell to a particular differentiation pathway

60
Q

as cells become gradually committed what happens?

A

certain genes are activated or inactivated

61
Q

of cell determination and differentiation which comes first?

A

cell determination

62
Q

what is morphogenesis?

A

the creation od shape/form (arms, legs, hands, etc)

63
Q

during development what happens to differentiated cells?

A

they become progressively organized into multicellular animals

64
Q

how does morphogenesis proceed?

A

through the processor pattern formation

65
Q

what is pattern formation?

A

a series of steps requiring signaling between cells, changes in cell shapes, precise cell migrations, interactions with the extracellular matrix, and apoptosis (the blueprint of the body (front and back))

66
Q

what is the principle of nuclear equivalence?

A

all somatic cells of an animal contains the same genetic information

67
Q

what does each cell type express?

A

different subset of the information

68
Q

what is differential gene expression responsible for?

A

variations in chemistry, behaviors and structure among cells

69
Q

which cells remain undifferentiated?

A

stem cells, giving them to ability to give rise to various cell types

70
Q

what happens in fertilization?

A

a motile sperm fuses with a ;large immotile ovum to produce a zygote

71
Q

what are the three important genetic consequence of fertilization?

A

restores diploid chromosome number, combines genetic information interactions from parents, and determines sex of offspring

72
Q

what does fertilization do to the egg?

A

activation, initiating reactions that permit development

73
Q

what are the four processes of fertilization?

A

sperm contacts egg, sperm or sperm nucleus enters the egg, egg becomes activated, and sperm and egg nuclei fuse

74
Q

what are the components of the sperm structure?

A

head, midpiece, ad tail

75
Q

what are components of the sperm head?

A

acrosome and nucleus

76
Q

what is a zone pellucida?

A

a noncellular layer (cell covering)

77
Q

what is an egg surrounded by?

A

a plasma membrane and one or more external coverings

78
Q

what is the purpose of egg coverings?

A

to offer protection and ensure fertilization of sperm of the same species

79
Q

what is the egg morphology? (contact and recognition)

A

jelly coat, vitelline envelope, plasma membrane, and cortical granules

80
Q

what two layers cover sea urchin eggs?

A

a vitelline envelope and a glycoprotein jelly coat

81
Q

what happens when sperm contacts the jelly coat?

A

an acrosome reaction where proteolytic enzymes digest through the jelly coat

82
Q

what are the last few stages of contact and recognition?

A

enzymes continue to digest through the jelly coat, binding to vitelline envelope, and membrane fusion

83
Q

what is the fertilization cone?

A

formed by the plasma membrane and draws the sperm into the egg

84
Q

what is polyspermy?

A

fertilization of the egg by more than one sperm causing an extra set of chromosomes, lethal

85
Q

what is fast block?

A

the egg plasma membrane depolarizes to prevent fusion with addition sperm causing electric shock

86
Q

what happens during fast block?

A

the egg is negatively charged, ion channels in the egg membrane open, and ion diffusion depolarizes the egg

87
Q

what is slow block?

A

calcium is release form the ER to trigger the release of cortical granules and the vitelline envelope lifts and forms the fertilization envelope as a physical barrier

88
Q

what happens during egg activation?

A

the release if calcium ions into the egg cytoplasm stimulates the cortical reaction and triggers the activation program, a series of metabolic changes in the egg; including the completion of meiosis

89
Q

what happens during egg and sperm fusion?

A

the completion of meiosis I the eggs forms the female pronucleus and the sperm nucleus swells to form the male pronucleus

90
Q

what happens to sperm in mammals?

A

it first undergoes capacitation, a maturation process in the female reproductive tract

91
Q

what is different for fertilization in mammals?

A

bindin-like proteins, cortical reaction alters “binding” sperm receptors so no more sperm can attach, and no fertilization envelope