6. The Membrane

The force driving simple diffusion is ________, while the energy source for active transport is ________.

A sodium-potassium pump ________.

Which of the following defines the type of transport by the sodium-potassium pump?

How are primary and secondary active transport related?

Suppose a cell is placed in a solution with a high concentration of potassium and no sodium. How would the cellular sodium–potassium pump function in this environment?

a. It would stop moving ions across the membrane.

b. It would continue using ATP to pump sodium out of the cell and potassium into the cell.

c. It would move sodium and potassium ions across the membrane, but no ATP would be used.

d. It would reverse the direction of sodium and potassium ions to move them against their gradients.

Which of the following forms of membrane transport require specific membrane proteins?

a. Diffusion

b. Exocytosis

c. Facilitated diffusion

d. Active transport

e. Facilitated diffusion and active transport

Which of the following cannot pass through the membrane without the help of a membrane protein?

a. Carbon dioxide

b. Water

c. Oxygen

d. Charged molecules