Mitochondrion has double membrane with an intermembrane space between outer and inner membrane. Cristae are the inner folds of membrane that jut out into matrix. Matrix is the innermost compartment of a mitochondrion and is filled with gel-like fluid. Most ATP produced in cellular respiration is produced in mitochondria. Transition reaction connects glycolysis to the Krebs cycle.
Reaction occurs twice for each original glucose molecule.
Krebs cycle reactions occur in matrix of mitochondria. Cycle is named for Sir Hans Krebs, who received Nobel Prize for identifying these reactions. NADH and FADH 2 carry these electrons to electron transport system. Some energy released is used to synthesize ATP by substrate-level phosphorylation, as in glycolysis. Krebs cycle turns twice for each original glucose molecule.