Cellular respiration begins with glucose. Glucose is the primary fuel used in glycolysis, the first stage of cellular respiration. This molecule is found in the gel-like substance called cytoplasm that fills the cell. In glycolysis, glucose undergoes phosphorylation by ATP. The ATP is converted back to ADP. The glucose molecule is rearranged and undergoes a second phosphorylation by ATP. The second ATP is also converted back to ADP. Glucose, a six-carbon molecule, is split into 2 …showed first 75 words of 370 total…

…showed last 75 words of 370 total…form water. As the electrons flow down the electron chain, they release energy that is used to make more ATP. Eight of the ten NADH form three ATP each, while the other two form two ATP. Each of the FADH2 form two ATP. The number of ATP produced here in the electron transport chain is 32. The total number of ATP is 38, but the use of two ATP in glycolysis gives a net gain of 36 ATP.