6. The Membrane

Which of the following processes includes all of the others?

The difference between simple and facilitated diffusion is that facilitated diffusion:

Which of the following does not accurately describe a channel or a carrier?

Which type(s) of molecules cannot enter/exit the cell via simple diffusion and require facilitated diffusion?

Based on Figure 7.18, which of these experimental treatments would increase the rate of sucrose transport into a plant cell?

a. Decreasing extracellular sucrose concentration

b. Decreasing extracellular pH

c. Decreasing cytoplasmic pH

d. Adding a substance that makes the membrane more permeable to hydrogen ions

Draw and label the plasma membrane of a cell that is placed in a solution with concentrations of calcium ions and lactose that are greater than those on the inside of the cell. Use arrows to show the relevant gradients and the activity of the following membrane proteins:

(1) A pump that exports protons

(2) A calcium channel

(3) A lactose carrier

In terms of structure, how do channel proteins differ from carrier proteins?

Facilitated diffusion across a membrane requires ______________ and moves a solute ______________ its concentration gradient.

a. transport proteins . . . up (against)

b. transport proteins . . . down

c. energy and transport proteins . . . up

d. energy and transport proteins . . . down