diffusion and active transportation

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.
Active transport is used to pump something against its concentration gradient, like a bunch of Na+ ions across a membrane. The Na+ ion gradient can then be used to drive something else like ion exchange (secondary active transport). So in this case, if the gradient increased in some way, the rate of secondary active transport could increase even if the ATP-driven active transport is unchanged.

An example that always comes up is the proton gradient driving ATP synthesis in the ETC.
 
Active transport depends on:

Concentration gradient
Electrical gradient
Amount of ATP
Number of channels, carrier proteins in the membrane

Diffusion depends on:

Concentration gradient
Surface area
Diffusion distance
Temperature
Pressure
 
Top