Ion Channels and ECG Flashcards Preview

MCM Test 1 > Ion Channels and ECG > Flashcards

Flashcards in Ion Channels and ECG Deck (10):
1

what molecules can permeate a phospholipid membrane?

gases, small uncharged polar molecules, sometimes water

2

what molecules cannot cross a phospholipid membrane without transporters?

large uncharged polar molecules, ions, charged polar molecules

3

what are some characteristics of protein transporters?

protein is specific for molecule transported
protein binding site/channel may open/close
protein conformational change required

4

what are energy sources for transporters?

ATP or concentration gradient

5

what cells is Na K ATPase present in?

all cells

6

how much of a cells ATP is used by Na K ATPase to establish ion gradients?

1/3

7

what does Na K ATPase transport and where?

Na from cytosol to extracellular space
K from extracellular space to cytosol

8

what are values of Km required to pick up a ligand?

Km lower than ligand conc.

9

what are values of Km required to drop off a ligand?

Km higher than ligand conc.

10

what are the steps of glucose transport from gut lumen through intestinal epithelium to blood?

1. Na K ATPase creates Na gradient so that the cytosol is Na depleted
2.Na glucose transporter allows Na to flow with gradient and drives glucose uptake from gut lumen against its gradient
3. glucose flows with gradient into blood through GLUT2
4. K channel allows K to flow with gradient to leave the cell