The Plasma Membrane And Membrane Potential

Question 1

Receptor sites on the outside of the plasma membrane are:

Answer 1

Proteins

Question 2

Which of the following are known to be second messengers?
A) Cyclic AMP 
B) Calcium 
C) ATP 
D) Both cyclic AMP and Calcium
E) All of these answers

Answer 2

D) Both cyclic AMP and Calcium

Question 3

Selective permeability of the membrane is primarily determined by:

Answer 3

The number and types of membrane potentials

Question 4

Carrier mediated transport:

Answer 4

Involves a specific membrane protein that serves as a carrier protein

Question 5

Facilitated Diffusion:

Answer 5

Is how glucose enters the cells and involves a carrier molecule

Question 6

What decreases the rate of diffusion for substance through a membrane?

Answer 6

Increasing the molecular weight of a substance

Question 7

The electrical gradient for K+:

Answer 7

• Favours its movement into the cell at resting potential

- Opposes the concentration gradient for K+ at the equilibrium potential for K+

Question 8

The concentration gradient for Na+:

Answer 8

• Favours its movement into the cell at resting potential

- Is maintained by the Na+ - K+ pump

Question 9

Which of the following does not require energy expenditure?
A) Net movement of potassium into the cell
B) Net movement of sodium into the cell
C) Iodine uptake by thyroid gland cells
D) Transport of hydrogen ion into the stomach lumen in association with hydrochloric acid secretion during digestion of a meal

Answer 9

B) Net movement of sodium into the cell

Question 10

Which of the following is not a function of membrane proteins?
A) They serve as channels
B) They determine the fluidity of the membrane
C) They serve as carriers
D) They serve as receptor sites
E) They serve as membrane-bound enzymes

Answer 10

B) They determine the fluidity of the membrane

Question 11

The phospholipids within the plasma membrane:

Answer 11

• Form a bilayer with the nonpolar tails buried in the centre and the hydrophilic heads lined up on the outer and inner surfaces
• Serve as a barrier to passage of water soluble substances between the ECF and ICF