Moving materials across the cell membrane sometimes requires energy, called active transport. This tutorial covers both primary and secondary active transport with good clear animations.

This lesson introduces the process of active transport, explaining that it is a form of transport that requires energy, and moves molecules against their concentration gradient. It is 4 of 4 in the series titled "Active Transport."

This lesson introduces the process of active transport, explaining that it is a form of transport that requires energy, and moves molecules against their concentration gradient. It is 1 of 4 in the series titled "Active Transport."

Through a combination of slide show tutorials and a video demonstration, learn how enzymes work. [3:00]