Membrane Transport

Question 1

A high partition coefficient (Kow) indicates that a molecule is

Answer 1

highly oil-soluble

Question 2

An aquaporin is

Answer 2

a transmembrane water channel constitutively allowing passive
diffusion

Question 3

An ion channel which opens when a molecule binds to it is

Answer 3

ligand-gated

Question 4

Two molecules being transported in the same direction across a
membrane is an example of

Answer 4

symport

Question 5

Facilitated diffusion generally requires

Answer 5

a change in conformation of a transmembrane carrier protein

Question 6

Rate of uptake via facilitated diffusion graph description

Answer 6

approaches an asymptote which indicates Vmax

Question 7

A low Km for a substrate indicates

Answer 7

high affinity for its transporter

Question 8

GLUT-1

Answer 8

ubiquitous- low Km for glucose

Question 9

GLUT-2

Answer 9

Liver, pancreatic beta cells- high Km and high Vmax for glucose

Question 10

GLUT-3

Answer 10

Brain- transports glucose in the brain

Question 11

GLUT-4

Answer 11

Muscle, adipocytes- insulin recruits transporter to membrane

Question 12

GLUT-5

Answer 12

Fructose

Question 13

GLUT1-4 transporters transport glucose via

Answer 13

facilitated diffusion

Question 14

The transporter with a high Km and high Vmax for glucose is useful

Answer 14

when blood glucose levels are high

Question 15

Na⁺/K⁺-ATPase in the sarcoplasmic reticulum is an example of

Answer 15

primary active transport

Question 16

The binding of sodium in Na⁺/K⁺-ATPase causes a conformational
change via

Answer 16

Autophosphorylation of the transporter

Question 17

A drug which blocks Na⁺/K⁺-ATPase is

Answer 17

oubain

Question 18

Heart failure may be helped by blockade of Na⁺/K⁺-ATPase due to

Answer 18

an increase in intracellular Ca²⁺ concentration

Question 19

SGLUT

Answer 19

important for the absorption of dietary glucose

Question 20

Na⁺/K⁺-ATPase moves

Answer 20

sodium out, potassium in, in a 3:2 ratio

Question 21

Secondary active transport is used in cholera treatment to

Answer 21

drive sodium replacement via a high intestinal glucose concentration

Question 22

Vibrio cholerae causes over-secretion of

Answer 22

Cl