what isprimary active transport?
- Anonymous9 years agoFavorite Answer
Proteins in the membrane can also act as pumps.
Move ions or small molecules from low concentration to high concentration (i.e. up their gradients).
Require cellular energy, usually as ATP
Saturates when substance reaches high concentrations due to lack of available protein.
Example: Na-K ATPase Present in nearly every cell in the body
Pumps 3 Na ions out in exchange for 2 K ions pumped in (cost=1 ATP)