CELL 3 Flashcards

1
Q

what is vesicular transport

A

using vesicles to move substance into / out of cell

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2
Q

what are 3 types of vesicular transport

A
  1. endocytosis
  2. exocytosis
  3. trasncytosis
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3
Q

ENDOCYTOSIS what is endocytosis

A

using vesicles to bring molecules into cell

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4
Q

ENDOCYTOSIS what are 3 types of endocytosis

A
  1. phagocytosis
  2. pinocytosis
  3. receptor-mediated endocytosis
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5
Q

ENDOCYTOSIS what is brought into cell in phagocytosis

A
  1. bacteria
  2. large particles
    (cell debris from damaged tissue)
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6
Q

ENDOCYTOSIS what are the steps of phagocytosis (5)

A
  1. pseudopodia surround bacteria or large particles
  2. vesicle pinches off from mem + internalized
  3. phagosome migrates to lysosome
  4. phagosome duses w lysosome
  5. vesicle contents digested by lysosome’s digestive enzymes
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7
Q

ENDOCYTOSIS what is internalized vesicle in phagocytosis called

A

phagosome

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8
Q

ENDOCYTOSIS what type of cell does phagocytosis

A

macrophages

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9
Q

ENDOCYTOSIS what do macrophages use phagocytosis for

A
  1. destroy bacteria

2. destroy cell debris found in blood

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10
Q

ENDOCYTOSIS what is brought into cell in pinocytosis

A
  1. solutes

2. water

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11
Q

ENDOCYTOSIS where do solutes and water that are brought in by pinocytosis come from

A

ECF

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12
Q

ENDOCYTOSIS what are the steps of pinocytosis (2)

A
  1. mem invaginates

2. pouch pinches off to form vesicle

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13
Q

ENDOCYTOSIS how is pinocytosis diff from phagocytosis

A
  1. pinocytosis does not use pseudopodia
  2. pinocytosis is non specific
  3. pinocytosis does not engulf large particles
  4. many cells in body do pinocytosis
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14
Q

ENDOCYTOSIS what are the steps of receptor mediated endocytosis (9)

A
  1. ligand binds to receptor on surface of PM
  2. clathrin links to receptor-ligand complex through adapter proteins
  3. clathrin- receptor- ligand complex forms cage-like structure
  4. receptor-ligand complexes accumulate in localized region of mem
  5. mem indents to form clathrin coated pit
  6. clathrin coared pit pinches off from mem to become clathrin coated vesicle
  7. vesicle loses clathrin coat
  8. clathrin recycles back to mem
  9. uncoated vesicle fuses w intracellular mems
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15
Q

ENDOCYTOSIS what organelle does uncoated vesicle often fuse with

A

endosome

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16
Q

ENDOCYTOSIS what happens when uncoated vesicle fuses w endosome

A

receptor + ligand dissociate

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17
Q

EXOCYTOSIS what are 3 functions of exocytosis

A
  1. secrete mem impermeable molecules that are synthesized by cell
  2. secrete waste products that cannot be digested
  3. replace portions of memm removed by endocytosis
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18
Q

EXOCYTOSIS why must endocytosis and exocytosis be balanced

A

to maintain overall size of PM over time

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19
Q

EXOCYTOSIS what are the steps of exocytosis (5)

A
  1. vesicle migrates to surface
  2. vesicle docks on peripheral mem proteins
  3. proteins pull PM inwards to form dimple
  4. dimple fuses w vesicle
  5. vesicle releases contents into ECF
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20
Q

TRASNCYTOSIS what is trasncytosis

A

using endocytosis and exocytosis to move receptor -bound molecule through cell

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21
Q

TRASNCYTOSIS what type of cell does trasncytosis

A

polarized cells

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22
Q

TRASNCYTOSIS what are polarized cells

A

cells w diff mems on its 2 sides

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23
Q

TRASNCYTOSIS what is best studied example of trasncytosis

A

absorption + transport of antibodies across epithelial lining of gut

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24
Q

TRASNCYTOSIS what are the steps of trasncytosis (8)

A
  1. antibody absorbed
  2. antibody binds to receptor on apical surface of intestinal cell
  3. antibody internalized by receptor mediated endocytosis
  4. receptor + antibody go to endosome
  5. receptor+ antibody go to recycling endosome
  6. receptor+antibody go to basal surface of cell
  7. receptor + antibody dissociate
  8. antibody enters blood
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25
Q

DRIVING FORCES what are 3 types of driving forces

A
  1. chemical
  2. electrical
  3. electrochemical
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26
Q

CHEMICAL DRVING FORCE when does conc gradient for substance exist

A

diff in conc of substance across mem

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27
Q

CHEMICAL DRVING FORCE what type of driving force is concentration gradient

A

chemical

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28
Q

CHEMICAL DRVING FORCE what direction do molecules of substance move

A

down conc gradient

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29
Q

CHEMICAL DRVING FORCE what direction is chemical driving force when there is higher conc inside than outside

A

directed out cell

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30
Q

CHEMICAL DRVING FORCE what direction is chemical driving force when there is higher conc outside than inside

A

directed into cell

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31
Q

CHEMICAL DRVING FORCE what happens as the size of conc gradient increases

A
  1. increase driving force

2. increase rate of transport

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32
Q

CHEMICAL DRVING FORCE what happens to potential energy as gradient eliminated

A

disappears

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33
Q

ELECTRICAL DRIVING FORCE why do electrical driving forces come about

A

mem potential

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34
Q

ELECTRICAL DRIVING FORCE what is mem potential

A

diff in electrical potential / voltage across mem

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35
Q

ELECTRICAL DRIVING FORCE what does mem potential reflect

A

unequal distribution of cations + anions across mem

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36
Q

ELECTRICAL DRIVING FORCE what does separation of charge refer to

A

unequal distribution of charges across mem

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37
Q

ELECTRICAL DRIVING FORCE as ion crosses mem what is it attracted to

A

net electric charge on one side of mem

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38
Q

ELECTRICAL DRIVING FORCE as ion crosses mem what does it repel

A

net electrical charge on other side of mem

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39
Q

ELECTRICAL DRIVING FORCE what does electrical driving force add to / subtract from

A

other driving forces that may be present

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40
Q

ELECTRICAL DRIVING FORCE what do electrical driving forces not act on

A

uncharged substances

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41
Q

ELECTRICAL DRIVING FORCE when is glucose transport affected by mem potential

A

when glucose coupled to movement of ion

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42
Q

ELECTROCHEMICAL DRIVING FORCE what are ions influenced by

A
  1. chemical driving force

2. electrical driving force

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43
Q

ELECTROCHEMICAL DRIVING FORCE what is electrochemical driving force

A

sum of chemical and electrical driving forces acting on ion

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44
Q

ELECTROCHEMICAL DRIVING FORCE what is direction of electrochemical driving force

A
  • net direction of electrical + chemical driving forces
  • if both in same direction ==> sum
  • if both in opposite direction ==> diff
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45
Q

CHANNELS what are characteristics of channels (6)

A
  1. multi meric proteins
  2. form pore that spans bilayer
  3. substrate specific
  4. exist in open or closed state
  5. allow for rapid movement
  6. can function as receptors
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46
Q

CHANNELS what is able to move through channels (2)

A
  1. ions

2. ion water complexes

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47
Q

CHANNELS what are aquaporins

A

channels that allow only water to pass through

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48
Q

CHANNELS what states do channels exist in

A
  1. open state

2. closed state

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49
Q

CHANNELS wha happens in open state

A

ion flow

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50
Q

CHANNELS what happens in closed state

A

no ion flow

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51
Q

CHANNELS why is there rapid movement across channels

A

low resistance pathway

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52
Q

CHANNELS why are channels able to act as receptors

A

able to bind ligand

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53
Q

CHANNELS what are channels that bind ligands called

A

ligand-gated ion channel

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54
Q

CHANNELS what happens when transmitter binds to receptor

A
  1. protein changes shape

2. protein allows flow of ions

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55
Q

CHANNELS what alters state of channel

A

ligand

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56
Q

CHANNELS what are 2 biological properties of channels

A
  1. gating

2. selectivity

57
Q

CHANNELS what does gating refer to

A
  1. opening by activation

2. closing by deactivation

58
Q

CHANNELS what does selectivity refer to

A

what species are allowed through channel

59
Q

CHANNELS what determines selectivity of channel

A
  1. diameter of central core

2. charge of aa s

60
Q

CHANNELS what are pores of channels filed with

A

water

61
Q

CHANNELS what do water-filled channels allow

A

stabilize ion as it passes through

62
Q

CHANNELS what is responsible for stabilizing ions as they pass through

A
  1. water

2. polar aa residues

63
Q

CHANNELS what does ability of ion-water complexed to pass through ion channels depend on

A
  1. charge

2. size

64
Q

SELECTIVITY FILTER what does charge selectivity depend on

A
  1. attraction to aa on inside of channel

2. repulsion to aa on inside of channel

65
Q

SELECTIVITY FILTER what is the function of selectivity filter

A

discriminate bw ions

66
Q

SELECTIVITY FILTER what does selectivity filter require ions to lose

A

hydration shell

67
Q

SELECTIVITY FILTER why does selectivity filter require ions to lose hydration shell

A

too big to pass though

68
Q

CHANNEL GATING what is channel gating

A

when a gate guards pore of channel

69
Q

CHANNEL GATING what are 3 types of gating

A
  1. voltage
  2. ligand
  3. stretch activated
70
Q

CHANNEL GATING what makes up voltage gate

A

sequence of aa

71
Q

CHANNEL GATING what is the function of sequence of aa s that make up voltage gate

A

act as voltage sensor

72
Q

CHANNEL GATING how does voltage gating work

A

channel opens in response to change in mem potential

73
Q

CHANNEL GATING how does ligand gating work

A

channel opens in response to ligand binding

74
Q

CHANNEL GATING how does stretch gating work

A

channel opens in response to cell stretching

75
Q

TRANSPORTER PROTEINS what is a transporter protein

A

proteins that have binding site for ligand

76
Q

TRANSPORTER PROTEINS what are characteristics of transporter proteins

A
  1. multi meric or mono meric
  2. spans bilayer
  3. substrate specific
  4. activity can be regulated
  5. can transport one or more substances
  6. can transport substances up or down concentration gradient
77
Q

TRANSPORTER PROTEINS how do transporter proteins compare to channels

A

slower

78
Q

TRANSPORTER PROTEINS what regulates activity of transporter proteins

A

effector molecules

79
Q

TRANSPORTER PROTEINS how do effector molecules work

A

induce conformational change that produces active or inactive form of transporter protein

80
Q

TRANSPORTER PROTEINS why are transporter proteins slower than channels

A

undergoes conformational changes

81
Q

TRANSPORTER PROTEINS (PASSIVE) what are GLUT proteins

A

glucose transporters

82
Q

TRANSPORTER PROTEINS (PASSIVE) why does glucose transport require transporter proteins

A
  1. polar
  2. uncharged
  3. large
83
Q

TRANSPORTER PROTEINS (PASSIVE) how does GLUT protein work (5)

A
  1. glucose binds to binding site on protein
  2. protein reoriented so binding site faces inside of cell
  3. glucose released into cell
  4. protein reoriented so binding site faces outside of cell
  5. protein can bind new glucose
84
Q

TRANSPORTER PROTEINS (PASSIVE) what does transport of glucose through GLUT protein depend on

A
  • high glucose conc outside

- low glucose conc inside

85
Q

ACTIVE TRANSPORT what are 2 forms of active transport

A
  1. primary

2. secondary

86
Q

ACTIVE TRANSPORT what do primary and secondary active transport use

A

transporter proteins

87
Q

ACTIVE TRANSPORT where does energy for primary active transport come from

A

ATP hydrolysis

88
Q

ACTIVE TRANSPORT where does energy for secondary active transport come from

A

electrochemical gradient

89
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP what are transporters called

A

ATP ase

90
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP why are transporters called ATP ase

A

catalyze break down of ATP

91
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens at the same time that transporters hydrolyze ATP

A

phosphorylate themselves

92
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP what does phosphorylation result in

A
  1. change in conformation

2. change in affinity of binding site for substrate

93
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP how many binding sites for Na on ATP ase

A

3

94
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP how many binding sites for K on ATP ase

A

2

95
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens in step one (4)

A
  1. binding sites face into cell
  2. pump has high affinity for Na
  3. pump has low affinity for K
  4. Na binds
96
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens in second step (2)

A
  1. ATP hydrolysis

2. ATP ase phosphorylated

97
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens in third step

A
  1. conformational change
  2. binding sites face outside cell
  3. release Na into ECF
98
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens in forth step

A
  1. pump has high affinity for K
  2. pump has low affinity for Na
  3. K binds
  4. ATP ase de phosphorylated
99
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens in fifth step

A
  1. conformational change

2. pump release K into ICF

100
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP why is sodium potassium pump electrogenic

A

there is net movement of charge during transport cycle

101
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP what is net movement of charge during transport cycle

A

1 pos charge out

102
Q

ACTIVE TRANSPORT PRIMARY NA / K PUMP what does sodium potassium pump contribute to

A
  1. establishing resting mem potential
  2. maintaining Na and K concentration gradients
  3. maintaining cell volume
103
Q

PUMPS LEAKS AND WATER what are concentration of Na and K at rest

A
  • high Na conc outside
  • low Na conc inside
  • high K conc inside
  • low K conc outside
104
Q

PUMPS LEAKS AND WATER what are impermeable proteins on inside of cell able to do

A

apply osmotic pressure that brings water into cell

105
Q

PUMPS LEAKS AND WATER why are Na and K able to act as impermeable proteins

A

concentrations maintained

  • high Na outside cell
  • high K inside cell
106
Q

PUMPS LEAKS AND WATER what plays a role in maintaining concentration gradients of Na and K

A

Na / K pump

107
Q

PUMPS LEAKS AND WATER what is direction of osmotic pull exerted by Na

A

out of cell

108
Q

PUMPS LEAKS AND WATER what is direction of osmotic pull exerted by K

A

into cell

109
Q

PUMPS LEAKS AND WATER how is osmotic water flow balanced

A
  1. water pulled into cell by impermeable proteins and K

2. water pulled out of cell by Na

110
Q

PUMPS LEAKS AND WATER what does cell ensure what does balance of osmotic water flow allow

A

constant volume

111
Q

ACTIVE TRANSPORT SECONDARY how does secondary active transport work

A

uses movement of ion down electrochemical gradient to drive movement of another molecule against conc gradient

112
Q

ACTIVE TRANSPORT SECONDARY what does secondary active transporter have binding sites for

A
  1. binding site for ion

2. binding site for transported molecule

113
Q

ACTIVE TRANSPORT SECONDARY how does sodium glucose symporter protein work

A
  1. transport Na into cell down electrochemical gradient

2. use released energy from electrochemical gradient to move glucose against concentration gradient (into cell)

114
Q

ACTIVE TRANSPORT SECONDARY what is co transport

A

2 molecules transported together

  • one down concentration gradient
  • one against concentration gradient
115
Q

ACTIVE TRANSPORT SECONDARY what is symporter

A

type of cotrasnporter

116
Q

ACTIVE TRANSPORT SECONDARY what is antiporter

A

type of cotransporter

117
Q

ACTIVE TRANSPORT SECONDARY how does sodium proton antiporter work

A
  1. transport Na into cell down electrochemical gradient

2. use released energy from electrochemical gradient to move proton against concentration gradient (out of cell)

118
Q

ACTIVE TRANSPORT SECONDARY why is sodium glucose symporter electrogenic

A
  • one pos charge brought in
119
Q

ACTIVE TRANSPORT SECONDARY why is sodium proton electro neutral

A
  • Na (pos) charge trasnported w proton (pos)
  • one pos charge brought into cell
    + one pos charge brought out of cell
120
Q

KINETICS OF TRANSPORT what is the relationship bw substrate concentration + transport rate

A

curvilinear relationship

121
Q

KINETICS OF TRANSPORT what happens as substrate concentration increases (before plateau)

A

rate of transport increases

122
Q

KINETICS OF TRANSPORT why does curve plateau

A

run out of binding sites

123
Q

KINETICS OF TRANSPORT what happens as substrate concentration increases (after plateau)

A

rate of transport doe not increase

124
Q

KINETICS OF TRANSPORT what is V max

A

max rate of transport

125
Q

KINETICS OF TRANSPORT how to obtain Vmax

A
  1. look to where curve plateaus

2. draw horizontal line to y axis

126
Q

KINETICS OF TRANSPORT what is Km

A

affinity of transporter for transported substrate

127
Q

KINETICS OF TRANSPORT what does affinity of transporter for transported substance indicate

A

strength of binding bw protein and substrate

128
Q

KINETICS OF TRANSPORT what does high affinity mean

A

substrate binds to protein more strongly

129
Q

KINETICS OF TRANSPORT what does low affinity mean

A

substrate binds to protein less strongly

130
Q

KINETICS OF TRANSPORT how to obtain Km

A
  1. divide V max by 2
  2. draw horizontal line to curve
  3. draw vertical line to x axis
131
Q

KINETICS OF TRANSPORT what does lower Km value mean

A

higher affinity

132
Q

KINETICS OF TRANSPORT what does higher Km value mean

A

lower affinity

133
Q

ADENOCARCINOMA what are nucleoside analogues used for

A

chemotherapt

134
Q

ADENOCARCINOMA what is gemcitabine

A
  • nucleoside analogue

- chemotherapy medication

135
Q

ADENOCARCINOMA what are hENT1 and hENT2 capable of

A

mediate gemcitabine uptake in direction of concentration gradient

136
Q

ADENOCARCINOMA what functionally distinguished hENTS

A
  1. hENT 1 inhibited by NBMPT

2. hENT 2 not inhibited by NBMPT

137
Q

ADENOCARCINOMA what are hCNT 1 and hCNT 2

A

nucleoside sodium co transporters

138
Q

ADENOCARCINOMA what is the function of hCNT 1 and hCNT 2

A

active transport of gemcitabine

139
Q

ADENOCARCINOMA what do hCNT 1 and hCNT 2 couple movement of gemcitabine with

A

Na down electrochemical gradient