1
Q
what is vesicular transport
A
using vesicles to move substance into / out of cell
2
Q
what are 3 types of vesicular transport
A
- endocytosis
- exocytosis
- trasncytosis
3
Q
ENDOCYTOSIS what is endocytosis
A
using vesicles to bring molecules into cell
4
Q
ENDOCYTOSIS what are 3 types of endocytosis
A
- phagocytosis
- pinocytosis
- receptor-mediated endocytosis
5
Q
ENDOCYTOSIS what is brought into cell in phagocytosis
A
- bacteria
- large particles
(cell debris from damaged tissue)
6
Q
ENDOCYTOSIS what are the steps of phagocytosis (5)
A
- pseudopodia surround bacteria or large particles
- vesicle pinches off from mem + internalized
- phagosome migrates to lysosome
- phagosome duses w lysosome
- vesicle contents digested by lysosome’s digestive enzymes
7
Q
ENDOCYTOSIS what is internalized vesicle in phagocytosis called
A
phagosome
8
Q
ENDOCYTOSIS what type of cell does phagocytosis
A
macrophages
9
Q
ENDOCYTOSIS what do macrophages use phagocytosis for
A
- destroy bacteria
2. destroy cell debris found in blood
10
Q
ENDOCYTOSIS what is brought into cell in pinocytosis
A
- solutes
2. water
11
Q
ENDOCYTOSIS where do solutes and water that are brought in by pinocytosis come from
A
ECF
12
Q
ENDOCYTOSIS what are the steps of pinocytosis (2)
A
- mem invaginates
2. pouch pinches off to form vesicle
13
Q
ENDOCYTOSIS how is pinocytosis diff from phagocytosis
A
- pinocytosis does not use pseudopodia
- pinocytosis is non specific
- pinocytosis does not engulf large particles
- many cells in body do pinocytosis
14
Q
ENDOCYTOSIS what are the steps of receptor mediated endocytosis (9)
A
- ligand binds to receptor on surface of PM
- clathrin links to receptor-ligand complex through adapter proteins
- clathrin- receptor- ligand complex forms cage-like structure
- receptor-ligand complexes accumulate in localized region of mem
- mem indents to form clathrin coated pit
- clathrin coared pit pinches off from mem to become clathrin coated vesicle
- vesicle loses clathrin coat
- clathrin recycles back to mem
- uncoated vesicle fuses w intracellular mems
15
Q
ENDOCYTOSIS what organelle does uncoated vesicle often fuse with
A
endosome
16
Q
ENDOCYTOSIS what happens when uncoated vesicle fuses w endosome
A
receptor + ligand dissociate
17
Q
EXOCYTOSIS what are 3 functions of exocytosis
A
- secrete mem impermeable molecules that are synthesized by cell
- secrete waste products that cannot be digested
- replace portions of memm removed by endocytosis
18
Q
EXOCYTOSIS why must endocytosis and exocytosis be balanced
A
to maintain overall size of PM over time
19
Q
EXOCYTOSIS what are the steps of exocytosis (5)
A
- vesicle migrates to surface
- vesicle docks on peripheral mem proteins
- proteins pull PM inwards to form dimple
- dimple fuses w vesicle
- vesicle releases contents into ECF
20
Q
TRASNCYTOSIS what is trasncytosis
A
using endocytosis and exocytosis to move receptor -bound molecule through cell
21
Q
TRASNCYTOSIS what type of cell does trasncytosis
A
polarized cells
22
Q
TRASNCYTOSIS what are polarized cells
A
cells w diff mems on its 2 sides
23
Q
TRASNCYTOSIS what is best studied example of trasncytosis
A
absorption + transport of antibodies across epithelial lining of gut
24
Q
TRASNCYTOSIS what are the steps of trasncytosis (8)
A
- antibody absorbed
- antibody binds to receptor on apical surface of intestinal cell
- antibody internalized by receptor mediated endocytosis
- receptor + antibody go to endosome
- receptor+ antibody go to recycling endosome
- receptor+antibody go to basal surface of cell
- receptor + antibody dissociate
- antibody enters blood
25
DRIVING FORCES what are 3 types of driving forces
1. chemical
2. electrical
3. electrochemical
26
CHEMICAL DRVING FORCE when does conc gradient for substance exist
diff in conc of substance across mem
27
CHEMICAL DRVING FORCE what type of driving force is concentration gradient
chemical
28
CHEMICAL DRVING FORCE what direction do molecules of substance move
down conc gradient
29
CHEMICAL DRVING FORCE what direction is chemical driving force when there is higher conc inside than outside
directed out cell
30
CHEMICAL DRVING FORCE what direction is chemical driving force when there is higher conc outside than inside
directed into cell
31
CHEMICAL DRVING FORCE what happens as the size of conc gradient increases
1. increase driving force
| 2. increase rate of transport
32
CHEMICAL DRVING FORCE what happens to potential energy as gradient eliminated
disappears
33
ELECTRICAL DRIVING FORCE why do electrical driving forces come about
mem potential
34
ELECTRICAL DRIVING FORCE what is mem potential
diff in electrical potential / voltage across mem
35
ELECTRICAL DRIVING FORCE what does mem potential reflect
unequal distribution of cations + anions across mem
36
ELECTRICAL DRIVING FORCE what does separation of charge refer to
unequal distribution of charges across mem
37
ELECTRICAL DRIVING FORCE as ion crosses mem what is it attracted to
net electric charge on one side of mem
38
ELECTRICAL DRIVING FORCE as ion crosses mem what does it repel
net electrical charge on other side of mem
39
ELECTRICAL DRIVING FORCE what does electrical driving force add to / subtract from
other driving forces that may be present
40
ELECTRICAL DRIVING FORCE what do electrical driving forces not act on
uncharged substances
41
ELECTRICAL DRIVING FORCE when is glucose transport affected by mem potential
when glucose coupled to movement of ion
42
ELECTROCHEMICAL DRIVING FORCE what are ions influenced by
1. chemical driving force
| 2. electrical driving force
43
ELECTROCHEMICAL DRIVING FORCE what is electrochemical driving force
sum of chemical and electrical driving forces acting on ion
44
ELECTROCHEMICAL DRIVING FORCE what is direction of electrochemical driving force
- net direction of electrical + chemical driving forces
- if both in same direction ==> sum
- if both in opposite direction ==> diff
45
CHANNELS what are characteristics of channels (6)
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
46
CHANNELS what is able to move through channels (2)
1. ions
| 2. ion water complexes
47
CHANNELS what are aquaporins
channels that allow only water to pass through
48
CHANNELS what states do channels exist in
1. open state
| 2. closed state
49
CHANNELS wha happens in open state
ion flow
50
CHANNELS what happens in closed state
no ion flow
51
CHANNELS why is there rapid movement across channels
low resistance pathway
52
CHANNELS why are channels able to act as receptors
able to bind ligand
53
CHANNELS what are channels that bind ligands called
ligand-gated ion channel
54
CHANNELS what happens when transmitter binds to receptor
1. protein changes shape
| 2. protein allows flow of ions
55
CHANNELS what alters state of channel
ligand
56
CHANNELS what are 2 biological properties of channels
1. gating
| 2. selectivity
57
CHANNELS what does gating refer to
1. opening by activation
| 2. closing by deactivation
58
CHANNELS what does selectivity refer to
what species are allowed through channel
59
CHANNELS what determines selectivity of channel
1. diameter of central core
| 2. charge of aa s
60
CHANNELS what are pores of channels filed with
water
61
CHANNELS what do water-filled channels allow
stabilize ion as it passes through
62
CHANNELS what is responsible for stabilizing ions as they pass through
1. water
| 2. polar aa residues
63
CHANNELS what does ability of ion-water complexed to pass through ion channels depend on
1. charge
| 2. size
64
SELECTIVITY FILTER what does charge selectivity depend on
1. attraction to aa on inside of channel
| 2. repulsion to aa on inside of channel
65
SELECTIVITY FILTER what is the function of selectivity filter
discriminate bw ions
66
SELECTIVITY FILTER what does selectivity filter require ions to lose
hydration shell
67
SELECTIVITY FILTER why does selectivity filter require ions to lose hydration shell
too big to pass though
68
CHANNEL GATING what is channel gating
when a gate guards pore of channel
69
CHANNEL GATING what are 3 types of gating
1. voltage
2. ligand
3. stretch activated
70
CHANNEL GATING what makes up voltage gate
sequence of aa
71
CHANNEL GATING what is the function of sequence of aa s that make up voltage gate
act as voltage sensor
72
CHANNEL GATING how does voltage gating work
channel opens in response to change in mem potential
73
CHANNEL GATING how does ligand gating work
channel opens in response to ligand binding
74
CHANNEL GATING how does stretch gating work
channel opens in response to cell stretching
75
TRANSPORTER PROTEINS what is a transporter protein
proteins that have binding site for ligand
76
TRANSPORTER PROTEINS what are characteristics of transporter proteins
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
TRANSPORTER PROTEINS how do transporter proteins compare to channels
slower
78
TRANSPORTER PROTEINS what regulates activity of transporter proteins
effector molecules
79
TRANSPORTER PROTEINS how do effector molecules work
induce conformational change that produces active or inactive form of transporter protein
80
TRANSPORTER PROTEINS why are transporter proteins slower than channels
undergoes conformational changes
81
TRANSPORTER PROTEINS (PASSIVE) what are GLUT proteins
glucose transporters
82
TRANSPORTER PROTEINS (PASSIVE) why does glucose transport require transporter proteins
1. polar
2. uncharged
3. large
83
TRANSPORTER PROTEINS (PASSIVE) how does GLUT protein work (5)
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
TRANSPORTER PROTEINS (PASSIVE) what does transport of glucose through GLUT protein depend on
- high glucose conc outside
| - low glucose conc inside
85
ACTIVE TRANSPORT what are 2 forms of active transport
1. primary
| 2. secondary
86
ACTIVE TRANSPORT what do primary and secondary active transport use
transporter proteins
87
ACTIVE TRANSPORT where does energy for primary active transport come from
ATP hydrolysis
88
ACTIVE TRANSPORT where does energy for secondary active transport come from
electrochemical gradient
89
ACTIVE TRANSPORT PRIMARY NA / K PUMP what are transporters called
ATP ase
90
ACTIVE TRANSPORT PRIMARY NA / K PUMP why are transporters called ATP ase
catalyze break down of ATP
91
ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens at the same time that transporters hydrolyze ATP
phosphorylate themselves
92
ACTIVE TRANSPORT PRIMARY NA / K PUMP what does phosphorylation result in
1. change in conformation
| 2. change in affinity of binding site for substrate
93
ACTIVE TRANSPORT PRIMARY NA / K PUMP how many binding sites for Na on ATP ase
3
94
ACTIVE TRANSPORT PRIMARY NA / K PUMP how many binding sites for K on ATP ase
2
95
ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens in step one (4)
1. binding sites face into cell
2. pump has high affinity for Na
3. pump has low affinity for K
4. Na binds
96
ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens in second step (2)
1. ATP hydrolysis
| 2. ATP ase phosphorylated
97
ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens in third step
1. conformational change
2. binding sites face outside cell
3. release Na into ECF
98
ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens in forth step
1. pump has high affinity for K
2. pump has low affinity for Na
3. K binds
4. ATP ase de phosphorylated
99
ACTIVE TRANSPORT PRIMARY NA / K PUMP what happens in fifth step
1. conformational change
| 2. pump release K into ICF
100
ACTIVE TRANSPORT PRIMARY NA / K PUMP why is sodium potassium pump electrogenic
there is net movement of charge during transport cycle
101
ACTIVE TRANSPORT PRIMARY NA / K PUMP what is net movement of charge during transport cycle
1 pos charge out
102
ACTIVE TRANSPORT PRIMARY NA / K PUMP what does sodium potassium pump contribute to
1. establishing resting mem potential
2. maintaining Na and K concentration gradients
3. maintaining cell volume
103
PUMPS LEAKS AND WATER what are concentration of Na and K at rest
- high Na conc outside
- low Na conc inside
- high K conc inside
- low K conc outside
104
PUMPS LEAKS AND WATER what are impermeable proteins on inside of cell able to do
apply osmotic pressure that brings water into cell
105
PUMPS LEAKS AND WATER why are Na and K able to act as impermeable proteins
concentrations maintained
- high Na outside cell
- high K inside cell
106
PUMPS LEAKS AND WATER what plays a role in maintaining concentration gradients of Na and K
Na / K pump
107
PUMPS LEAKS AND WATER what is direction of osmotic pull exerted by Na
out of cell
108
PUMPS LEAKS AND WATER what is direction of osmotic pull exerted by K
into cell
109
PUMPS LEAKS AND WATER how is osmotic water flow balanced
1. water pulled into cell by impermeable proteins and K
| 2. water pulled out of cell by Na
110
PUMPS LEAKS AND WATER what does cell ensure what does balance of osmotic water flow allow
constant volume
111
ACTIVE TRANSPORT SECONDARY how does secondary active transport work
uses movement of ion down electrochemical gradient to drive movement of another molecule against conc gradient
112
ACTIVE TRANSPORT SECONDARY what does secondary active transporter have binding sites for
1. binding site for ion
| 2. binding site for transported molecule
113
ACTIVE TRANSPORT SECONDARY how does sodium glucose symporter protein work
1. transport Na into cell down electrochemical gradient
| 2. use released energy from electrochemical gradient to move glucose against concentration gradient (into cell)
114
ACTIVE TRANSPORT SECONDARY what is co transport
2 molecules transported together
- one down concentration gradient
- one against concentration gradient
115
ACTIVE TRANSPORT SECONDARY what is symporter
type of cotrasnporter
116
ACTIVE TRANSPORT SECONDARY what is antiporter
type of cotransporter
117
ACTIVE TRANSPORT SECONDARY how does sodium proton antiporter work
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
ACTIVE TRANSPORT SECONDARY why is sodium glucose symporter electrogenic
- one pos charge brought in
119
ACTIVE TRANSPORT SECONDARY why is sodium proton electro neutral
- Na (pos) charge trasnported w proton (pos)
- one pos charge brought into cell
+ one pos charge brought out of cell
120
KINETICS OF TRANSPORT what is the relationship bw substrate concentration + transport rate
curvilinear relationship
121
KINETICS OF TRANSPORT what happens as substrate concentration increases (before plateau)
rate of transport increases
122
KINETICS OF TRANSPORT why does curve plateau
run out of binding sites
123
KINETICS OF TRANSPORT what happens as substrate concentration increases (after plateau)
rate of transport doe not increase
124
KINETICS OF TRANSPORT what is V max
max rate of transport
125
KINETICS OF TRANSPORT how to obtain Vmax
1. look to where curve plateaus
| 2. draw horizontal line to y axis
126
KINETICS OF TRANSPORT what is Km
affinity of transporter for transported substrate
127
KINETICS OF TRANSPORT what does affinity of transporter for transported substance indicate
strength of binding bw protein and substrate
128
KINETICS OF TRANSPORT what does high affinity mean
substrate binds to protein more strongly
129
KINETICS OF TRANSPORT what does low affinity mean
substrate binds to protein less strongly
130
KINETICS OF TRANSPORT how to obtain Km
1. divide V max by 2
2. draw horizontal line to curve
3. draw vertical line to x axis
131
KINETICS OF TRANSPORT what does lower Km value mean
higher affinity
132
KINETICS OF TRANSPORT what does higher Km value mean
lower affinity
133
ADENOCARCINOMA what are nucleoside analogues used for
chemotherapt
134
ADENOCARCINOMA what is gemcitabine
- nucleoside analogue
| - chemotherapy medication
135
ADENOCARCINOMA what are hENT1 and hENT2 capable of
mediate gemcitabine uptake in direction of concentration gradient
136
ADENOCARCINOMA what functionally distinguished hENTS
1. hENT 1 inhibited by NBMPT
| 2. hENT 2 not inhibited by NBMPT
137
ADENOCARCINOMA what are hCNT 1 and hCNT 2
nucleoside sodium co transporters
138
ADENOCARCINOMA what is the function of hCNT 1 and hCNT 2
active transport of gemcitabine
139
ADENOCARCINOMA what do hCNT 1 and hCNT 2 couple movement of gemcitabine with
Na down electrochemical gradient
PHYSL 212
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