Hi all!

In our biological system are there two types of energy? One is Free energy and another is energy in the form of ATP.

In this context it state that:

Under: Passive transport across membrane

A transporter protein reduces the Delta G (free energy) for transmembrane diffusion of the solute. Does that mean that energy or free energy is still needed so that diffusion of the solute can work since it is just lowering down the free energy?

Where does free energy come from to drive diffusion?

And are there energy in the form of "something else" instead of ATP?

And since active transport require energy (in the form of ATP) to work, so does free energy still needs to be involve in this reaction?