Question

What is the ultimate source of free energy for secondary active transport?

Answer 1

Secondary active transport , is transport of molecules across the cell membrane utilizing energy in the form other than ATP.

- so this energy comes from the electrochemical gradient created by pumping ions out of the cell. This type of transport is also called co-transport.

There are two types of active transport. (1) symport and antiport

The formation of electrochemical gradient is done by primary active transport of sodium which enables the co-transport.

- Sodium is actively transported out of the cell creating a much higher concentration in extracellular than intracellular.

- This gradient becomes energy as the excess sodium is constantly being trying to diffuse in to the cell interior.

Hope you got your answer , thanks.