B3

Active Transport

This allows substances to move against a concentration gradient (from an area of low concentration to and area of high concentration) meaning cells can absorb ions from dilute solutions and move things like sugar and ions through the cell membranes.

How it works

A transport protein in the cell membrane selects the solute molecule to be transported, rotates in the the membrane (requiring energy) and releases it into the cell. It then rotates back again. This process needs…