Final answer:
The inner membrane of the mitochondrion is where electron transport and oxidative phosphorylation occur.
Step-by-step explanation:
The metabolic functions of electron transport and oxidative phosphorylation occur in the inner membrane of the mitochondrion. The inner membrane contains folds called cristae, which increase its surface area. The space between the two membranes is called the intermembrane space, and the space inside the inner membrane is called the matrix. Electron transport takes place on the inner membrane, while oxidative phosphorylation uses the proton gradient across the inner membrane to synthesize ATP.