Clinical Relevance Cell Membranes & Transport

Question 1

What are the factors that influence membrane fluidity?

Answer 1

Temperature
Lipid composition
Cholesterol

Question 2

In membrane fluidity, how can proteins and lipids move?

Answer 2

Rotate and move laterally

Question 3

________ can either increase or decrease membrane fluidity.

Answer 3

Cholesterol

Question 4

If membrane is too (FLUID/RIGID) (due to higher saturated FAs or temp below Tm), cholesterol intercalates into membrane and increases fluidity by preventing close packing of the lipids.

Answer 4

Rigid

Question 5

If membrane is too (FLUID/RIGID) (due to high content of unsaturated FAs) cholesterol stabilizes fluidity by fitting in gaps created by kinds in the tail lipids.

Answer 5

Fluid

Question 6

Cardiac glycosides such as _______ and the more lipophilic drug ________ acts as cardiotonic (contraction-inducing) drugs.

Answer 6

Ouabain

Digoxin

Question 7

Cardiotonic drugs inhibit the __________ in cardiac myocytes. This leads to an increase in intracellular Na+. This impairs the activity of the secondary transporter called _______, because it is coupled to the _________.

Answer 7

Na/K-ATPase
NCX (Sodium Calcium Exchanger)
Na/K-ATPase

Question 8

Impairment of the NCX leads to a secondary increase in _______ in the SER. This stimulates the heart muscle to contract. Help in heart attack situations.

Answer 8

Calcium