Question

Why is it important there is a concentration gradient of H's across the mitochondrial membrane?

Answer 1

See below.

Explanation:

The hydrogen ions (`"H"^+`)are all positively charged and are collected on one side of the membrane. The electrons are all negatively charged and are collected on the other side of the membrane. This makes the hydrogen ions want to go to the other side of the membrane, which ATP synthase takes advantage of - whenever a hydrogen crosses the membrane through ATP synthase, a lot of ATP and water is produced (but most importantly the ATP).

I hope that helps!