Movement of substances across a cell membrane

Osmosis

• involves the movement of solute molecules across a membrane.

• is a special form of diffusion.

• requires metabolic energy.

• involves the movement of water across a membrane.

Sucrose solution

• has a water potential equals to 0.

• has a water potential lower than 0.

• has a water potential higher than 0.

As compared to a dilute sucrose solution, a concentrated sucrose solution

• has a water potential higher than the dilute sucrose solution.

• has a water potential lower than the dilute sucrose solution.

• has the same water potential of the dilute sucrose solution.

Which solution, the one on left or the one on right, has a higher water potenital?

• the one on the left

• the one on the right

What is the direction of osmosis?

• From left side to right side.

• From right side to left side.

If the membrane in between the two solution was damaged,

• water molecules can still move from left to right.

• water molecules can still move from right to left.

• sucrose molecules cannot move across the barrier.

• sucrose molecules can move with no barrier.

Active transport is similar to facilitated diffusion

• as channel proteins are involved.

• as carrier proteins are involved.

• as metabolic energy is not required.

• as metabolic energy is needed.

Active transport is different from facilitated diffusion

• as one requires metabolic energy while the other does not.

• as channel proteins are involved in one of the two processes.

• as folding of cell surface membrane is involved in one of the two processes.