The main substrate within the respiration pathway is glucose.
The metabolic pathway involved in respiration can be split into three main parts:
Glycolysis - occurs in the cytoplasm.
Citric acid cycle - occurs in the matrix of the mitochondriaStructures in the cytoplasm of all cells where aerobic respiration takes place (singular is mitochondrion)..
Electron transport chain - occurs in the inner membrane of the mitochondria.