Inner mitochondrial membrane: This is where cristae reside; it separates matrix from intermembrane space, much like walls separate different rooms in an office building.
Oxidative phosphorylation:This process happens on cristae and produces ATP from nutrients, similar to how work done in offices leads to completed projects or products.
Proton gradient: Created across cristae during electron transport chain, it's like the motivation or driving force that gets work done in an office.