Membrane Potentials / Synpases

Question 1

lipid bilayer is [a] to ions so ions have to use [b,c,d] to get through the membrane

Answer 1

a) impermeable
b,c,d) channels, transporters, pumps!

Question 2

Channels

Answer 2

transport ions DOWN transportation gradient, passive, high to low, open hole

FASTEST

Question 3

Transporters

Answer 3

3 types– uniporter, symporter, antiporter
not always open, ligand binds and conformational change

Question 4

uniporter

Answer 4

one ion down concentration gradient

Question 5

symporter

Answer 5

2 ions in the same direction, one molecule down concentration gradient, one molecule against

Question 6

antiporter

Answer 6

2 ions opposite direction, one molecule down concentration gradient, one molecule against

Question 7

Pumps

Answer 7

use ATP… ACTIVE

ATP hydrolysis to power movement of specific ions or small molecules against electrochemical gradient

Question 8

Many channels are gated, what are the gating types?

Answer 8

voltage gated: open + close in response to transmembrane potential changes

ligand gated: open + close in response to ligand
ie. NT

“Other gated” such as thermal or mechanical

Question 9

Leak channel

Answer 9

constitutively open, maintain resting potential

Question 10

Membrane potential is determined by

Answer 10

movement of ions down their electrochemical gradients through ion channel

Question 11

Membrane potential is measured what relative to what

Answer 11

cytosol to extracellular fluid

Question 12

Electrochemical gradient

Answer 12

transmembrane potential + concentration gradient

sum of electric gradient and concentration gradient free energy change when a given ion moves frm one side of membrane to other

Question 13

(a) establishes the concentration gradient

Answer 13

Na-K ATPase

Question 14

equilibrium potential

Answer 14

refers to ONE ion

the transmembrane potential at which concentration gradient is equal nad opposite to the electrical gradient =