Active Transport

Definition: the movement of molecules or ions into or out of a cell from a region of lower concentration to a region of higher concentration using ATP and carrier proteins.

• Active process (requires metabolic energy = ATP)
• Directly moves molecules
• Against a conc. gradient (low to high)
• Carrier protein molecules act as 'pumps'
• Selective process 

Direct:

• Ions bind to the carrier proteins receptors
• Inside the cell, ATP binds to the protein, which is then…