What are the main steps in aerobic respiration? Where does it take place?
The main steps in aerobic respiration are: Glycolysis occurring in the cytoplasm where glucose is broken into pyruvate; transport of pyruvate into the mitochondria and its conversion to acetyl CoA with release of CO₂; Krebs' cycle operating in the matrix of mitochondria where complete oxidation of pyruvate occurs by stepwise removal of hydrogen atoms, releasing CO₂ and generating NADH + H⁺ and FADH₂; and finally the Electron Transport System (ETS) located on the inner membrane of mitochondria where electrons are passed to molecular O₂ with simultaneous synthesis of ATP.
Aerobic respiration takes place primarily in the mitochondria in eukaryotes. The initial stage (glycolysis) occurs in the cytoplasm, while the subsequent steps—Krebs' cycle in the matrix and ETS on the inner membrane—take place within the mitochondria.
Explanation
The textbook context clearly outlines that aerobic respiration involves complete oxidation of organic substances in presence of oxygen. The crucial events include complete oxidation of pyruvate with removal of hydrogen atoms and passing electrons to O₂ for ATP synthesis. The location is explicitly stated: glycolysis in cytoplasm, and the remaining processes within mitochondria (Krebs' cycle in matrix, ETS on inner membrane).