* Cytoplasm: The first stage of aerobic respiration, glycolysis, occurs in the cytoplasm. Glycolysis breaks down glucose into pyruvate.
* Mitochondria: The subsequent stages of aerobic respiration, the Krebs cycle and oxidative phosphorylation, occur in the mitochondria.
Let's break it down further:
* Krebs cycle: This cycle takes place in the mitochondrial matrix, the inner space of the mitochondria. It further breaks down pyruvate, producing ATP, NADH, and FADH2.
* Oxidative phosphorylation: This final stage occurs on the inner mitochondrial membrane. It uses the electron carriers NADH and FADH2 generated in the Krebs cycle to power a proton gradient across the membrane, which is then used to generate ATP.
So, while glycolysis starts in the cytoplasm, the bulk of aerobic respiration, generating the majority of ATP, takes place in the mitochondria.
