Glucose stores the sun's energy in chemical form. Adenosine triphosphate - ATP the molecule most organisms can actually use for energy. Respiration the breaking down of pyruvic acid using molecular oxygen.
Respiration occurs in the mitochondria of cells.
O Fermentation - the breaking down of pyruvic acid without using molecular oxygen. This process does not require the presence of molecular oxygen. The Electron Transport Chain then produces 34 ATP molecules and H 2 O from the carrier molecules. The bulk of a cell's ATP must be produced in the mitochondria. To be energy efficient, particles must move through the membrane with little energy expense.