Active Transport

Active transport is when cells must move materials against a concentration gradient. This means regardless of molecules outside or in the cell, the molecules are moved to where they need to be. Think of this as a Fedex delivery, even though you could have a ton of packages inside your house, the delivery guy will still need to get out of the truck, ring the bell to your house, wait for you to open the door and sign for the package, and leave the package.

Active transport requires energy (that is why its called active).

I did not create this animation. It comes from phschool and can be accessed directly at http://www.phschool.com/atschool/phbio/active_art/active_transport/index.html