The concentration gradient of a substance across the membrane represents potential energy bcz it drives diffusion.Transport proteins aids the diffusion.
Digestion converts chemical energy into kinetic energy used by cells.
When the electrons are destroyed in the glucose,Energy contained in the bonds is released in small bursts,some of it is captured in the form of ATP .'The electrons are transferred to smaller molecules known as electron carriers.The electron carriers take the electrons to a group of proteins in the inner membrane of the mitochondrion,called the electron transport chain.As electrons move through the electron transport chain they go from a higher to lower energy level and are finally passed to Oxygen to form water.The energy released is captured as a proton gradient which powers the production of ATP.
On the graph in plato the y axis starts on 8, so that is our initial height. the graph starts to go lower to ground level until it reaches the 12 on the x axis, this is where the skateboarders would meet ground level on the ramp, and obviously the graph is all positive numbers so the start of the ramp would be on the left edge.