Which requires the use of energy to move a molecule across a cell membrane?

Answer 1

No. Water molecules can osmotically cross the cell membrane because they are small enough that their polarity does not matter. Then there are porins. Channels across the cell membrane that water molecules use.

Answer 2

No, energy is not required because the cell membrane is semi-permeable and allows water molecules (or any solvent molecule) to pass through it from their region of higher concentration to their region of lower concentration (process-osmosis).

Answer 3

Energy is required when the substance is travelling against a concentration gradient. This means there are more molecules on the other side of the membrane, where the substance is being moved to.

Answer 4

No. Some water molecules, because they are small, can cross the membrane by osmosis. Then there are the channels called porins that allow water molecules to cross the membrane.

Answer 5

I believe there is here in my textbook it says yes so YES

Answer 6

1) When the osmotic gradient points in the opposite direction.

2) When the membrane is NOT permeable to that molecule and active transport is required.

Answer 7

Active transport

Answer 8

active transport

Answer 9

Active transport