SM37

Question 1

Types of membrane transport

Answer 1

active transport, passive transport, facilitative diffusion, secondary active transport

Question 2

Types of channels

Answer 2

voltage-gated ion channels, ligand-gated ion channels, leak channels, water channels

Question 3

Two broad categories for ion translocating ATPases (e.g. ion pumps)

Answer 3

P-type ATPases (Na/K, Ca, H/K) and V-type ATPases (proton pumps, v for vacuolar)

Question 4

Membrane transporters besides ion pumps and channels

Answer 4

Uniporters (aka carriers), antiporters (aka exchangers), symporters (aka co-transporters)

Question 5

Symporters and antiporters can be either _____ or ______ depending on whether they alter the balance of charge

Answer 5

electroneutral (no net change in balance of electrostatic charges) or electrogenic (balance of charges altered)

Question 6

General classes of ion channels with role in setting resting membrane potential

Answer 6

K+ leak channels (inward rectifier and twin-pore), Na+ leak channels

Question 7

General classes of ion channels with molecular basis in action potential

Answer 7

Voltage gated Na+ and K+ channels

Question 8

Phenomenon where proteins assemble to conduct an ion more effectively in the inward direction than outward

Answer 8

inward rectification

Question 9

Sulfonylurea receptors are what type of receptor? What happens in the presence of low ATP levels?

Answer 9

(aka K-atp. Sulfonyl urea is a class of drugs used to treat diabetes mellitus)

Inward rectifying K+ channels inhibited by intracellular ATP. At low ATP levels, potassium efflux occurs, and hence membrane hyperpolarization

Question 10

What are GIRK channels?

Answer 10

inward rectifying K+ channels activated by G-protein signaling. These channels act as effectors for GPCRs

Question 11

How are K-atp channels related to insulin secretion?

Answer 11

In pancreatic islet Beta-cells, sulfonylureas inhibit K-atp channels and permit membrane depolarization to elicit insulin secretion.