Final answer:
Glycolysis occurs in the cytoplasm; the citric acid cycle happens in the mitochondrial matrix; the electron transport chain is in the cristae of the mitochondria.
Step-by-step explanation:
Glycolysis occurs in the cytoplasm, the citric acid cycle takes place in the mitochondrial matrix, and the electron transport chain is located in the cristae of the mitochondrion. Glycolysis is the initial stage of cellular respiration and happens in the cytoplasm, where glucose gets converted into pyruvate while yielding energy in the form of ATP.
The pyruvate then enters the mitochondria, where it undergoes a transformation into acetyl CoA, which feeds into the citric acid cycle. Imperative to this cycle are the series of redox, dehydration, hydration, and decarboxylation reactions that generate molecular energy carriers such as ATP, NADH, and FADH₂ within the mitochondrial matrix. These carriers are crucial for the electron transport chain on the inner membrane, also known as cristae. The electron transport chain culminates the energy extraction process, using the electrons transferred from NADH and FADH₂ to synthesize a significant amount of ATP, the cell's energy currency, through oxidative phosphorylation.