BB451 exam 1 - Membrane Transport

Question 1

entropy

Answer 1

diffusion

Question 2

symports

Answer 2

pumps that move molecules in same direction

Question 3

antiports

Answer 3

move 2 molecules in opposite directions

Question 4

electroneutral

Answer 4

does not result in net change in charge

Question 5

electrogenic

Answer 5

changes charge across membrane

Question 6

glucose transporter in blood cells

Answer 6

passive transport

let’s glucose diffuse into cells, no energy (generally more glucose in fluid around blood cells)

Question 7

P-type ATP using transport systems use ____ as a covalent intermediate

Answer 7

phosphoaspartate

Question 8

Calcium ATPase

Answer 8

ATP bind to Ca
transfer of phosphate from ATP to aspartic acid –>phosphoaspartate
ADP leaves and protein changes shape –> Ca moves across membrane
hydrolysis of phosphate from aspartic acid side chain –> protein back to original state
symport

Question 9

sodium glucose pump

Answer 9

uses sodium gradient (made by Na/K ATPase) to bring in glucose against it’s gradient
*active transport with no ATP

Question 10

lactose permease pump

Answer 10

bacteria use to bring in lactose
lactose carried in against gradient using gradient of protons (higher out than in)
*active transport with no ATP

Question 11

sodium glucose pump and lactose permease pump are ___

Answer 11

secondary transporters
energy to move glucose or lactose from concentration gradient of carrier molecules (Na or H+) and electrical forces that drive ions into cell

Question 12

heart muscle has …

Answer 12

pump that pumps Ca out of cell using sodium gradient = sodium calcium pump
antiport: Na in as Ca moves out

Question 13

digitoxigenin

Answer 13

inhibits Na/K ATPase –> reducing Na gradient
reduces export of Ca from heart cells
in small amounts: used to treat congestive heart failure, causes heart to contract more forcefully
from foxglove

Question 14

ABC transporters

Answer 14

have domains labeled A,B,C
ex: multidrug resistance protein - works on variety of drugs, kicks drug out of cell
involved in resistance of cancer cells to chemo

Question 15

Nerve transmission relies on

Answer 15

sodium potassium gradient

Question 16

in nerve transmission, gates open/close to…

Answer 16

allow Na to diffuse into nerve cells and K to diffuse out

Question 17

step 1 nerve transmission

Answer 17

open Na gates

-Na into cell, depolarization

Question 18

step 2 nerve transmission

Answer 18

K gates open, Na gates close

• K flows out of cell, repolarization
• overcompensation in voltage past resting potential

Question 19

step 3 nerve transmission

Answer 19

K gates close

• recovery phase
• recovers voltage by Na/K ATPase

Question 20

transmission between nerve cells

Answer 20

as result of wave of Na arriving at end of cell
synaptic vesicles fuse with end of nerve cell
release neurotransmitters into synaptic cleft
neurotransmitters interact with receptors on next cell
stimulate opening of Na gates –> same process

Question 21

tetrodotoxin

Answer 21

sodium channel inhibitor from puffer fish

Question 22

Potassium is ___ than sodium

Answer 22

bigger

Question 23

how to keep sodium out of potassium gate

Answer 23

rooted in energy
goes through desolvation (shed water) and resolvation
if moving through/resolvation generates more energy than it takes for desolvation –> favored (potassium)

Question 24

how to keep potassium out of sodium gate

Answer 24

potassium is too big to fit through Na gate

regulated by size