Week 5- Ion channels/ PBL- Fitz Flashcards Preview

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Flashcards in Week 5- Ion channels/ PBL- Fitz Deck (12):
1

Compare and contrast ion channels and transporters

ION CHANNELS:
holes in membrane
transports small things
flow is always passive
does NOT require energy
goes DOWN electrochemical gradient
Transports at high rates

TRANSPORTERS:
Never opens to both sides of the membrane at the same time
Can trasport ion but ALSO large molecules
Can be passive but can also be ACTIVE, goes AGAINST gradients
transports at slower rates
establishes gradients

2

What are the critical features of ion channels?

Selectivity- differ in number and type of ions that will pass
Gating- structure opens and closes channels
Inactivation- only some channels have, can prevent flow of ions through channel
Bidrectional Flow

3

Rank extracellular concentrations of ions

Na > Cl > K > Ca

4

How do you determine reversal potential?

Reversal Potential= 61/z log (concentation outside/ concentration inside)

z= electrical charge of ion

5

Define depolarization and hyperpolarization

depolarization makes membrane potential more POSITIVE

hyperpolarization makes the membrane potential more NEGATIVE

6

What is ohms law?

V=IR
voltage = current (voltage) x resistance

7

What are the different types of gating?

leaky
mechanical
ligan
voltage gated
spontaneous

8

Normal flow of primary electrolytes based on concentrations

Na flows into cell
K flow out of the cell
Ca+2 flows into cell
Cl- flows into cell

9

Reversal Potential for Na

+60

10

Reversal Potential for K+

-88

11

Reversal Potential for Ca+

+214

12

Reversal Potential for Cl-

-61