Explain how the structures of a mitochondrion and a ribosome are related to their functions in a eukaryotic cell.

Mitochondria are double‑membrane organelles; the outer membrane is smooth while the inner membrane is highly folded into cristae, increasing surface area for the electron‑transport chain and ATP synthase. This structure allows mitochondria to be the site of aerobic respiration, producing ATP that supplies energy to the cell. Cells with high energy demands, such as muscle cells, contain many mitochondria, linking quantity to function.

Ribosomes are small, dense complexes of rRNA and proteins. They are found either free in the cytosol or bound to the rough endoplasmic reticulum. Their structure provides the catalytic site for peptide bond formation, making them the site of protein synthesis. Cells that produce large amounts of protein, such as secretory cells, contain many ribosomes, again linking quantity to function.