In cellular respiration, glucose first undergoes glycolysis and is broken down into two pyruvate molecules. As the pyruvate passes through the citric acid cycle, three molecules of are produced. The radioactive oxygen molecules would be found in the .

is formed when electrons removed from glucose are used to reduce . is produced by the phosphorylation of . The oxygen in enters the mitochondrion as gaseous molecular oxygen from the atmosphere, not from glucose. Finally, is reduced to water in cellular respiration and serves as a reactant, rather than a product, in cell metabolism.

Upon completion of the citric acid cycle, 1 molecule of , 2 molecules of , 3 molecules of , and 1 molecule of are produced. is not produced during the citric acid cycle. is the product of the pentose phosphate pathway. is a powerful reducing agent used in several metabolic pathways. For example, it is used in red blood cells to reduce glutathione. Note that the products listed above represent those from one turn of the citric acid cycle; each molecule of glucose produces two molecules of acetyl-CoA, thus the cycle turns twice per glucose molecule.

Glycolysis generates four ATP per molecule of glucose and uses up two of those in the process, while oxidative phosphorylation produces thirty-two ATP per molecule of glucose. Fermentation produces NAD+, which is used in glycolysis. The citric acid cycle produces NADH and FADH2, which are used in the electric transport chain. Note that for each turn of the citric acid cycle, three NADH molecules and one FADH2 molecule is produced, but each glucose produces two pyruvate molecules, which are converted to two acetyl-CoA molecules. Each acetyl-CoA molecule results in one full turn of the citric acid cycle. The electron transport chain produces an electrochemical gradient across the inner membrane of the mitochondria, which provides the energy used by oxidative phosphorylation to produce thirty-two ATP per molecule of glucose.

The citric acid (Krebs) cycle takes place in the mitochondrial matrix. The Krebs cycle involves using acetyl-CoA as a substrate to produce high energy electron carriers and to later participate in electron transport, ultimately yielding . Glycolysis is the process by which glucose is split into two molecules of pyruvate, and occurs in the cytoplasm. The electron transport chain performs its function in the inner mitochondrial membrane. The nucleus and ribosomes are not part of the citric acid cycle.

Acetyl-CoA is formed when two carbon atoms join to coenzyme A. Ribose is a five carbon sugar in RNA. ATP is an energy compound, and FAD is an electron carrier in the Krebs cycle which gets reduced then passes its electron to an enzyme complex in the electron transport chain.

Carbon dioxide is the gas produced in the Krebs cycle, which animals exhale. Oxygen is used as an electron acceptor, while nitrogen is not a waste gas. Carbon monoxide is not a waste product in the Krebs cycle.

This is because during glycolysis, a glucose molecule produces 2 ATP, 2 NADH, and 2 pyruvate. The 2 pyruvate created are used again to create 8 NADH, 2 FADH2, and 2 ATP during the Krebs cycle to net 10 NADH, 4 ATP, 2 FADH2.

The answer to this question is is reduced.

is least likely to occur because it is already in its reduced form. In actuality, it gets oxidized, as pyruvate is reduced into lactic acid. These other events are likely to occur. Your body does lack oxygen and lactate and ATP are produced in order to make up for the debt of oxygen. also is recycled to be used in glycolysis so this event is also not least likely to occur.

The Krebs cycle takes place in the mitochondria. The Golgi apparatus packages substances in order for them to be sent to their appropriate locations, and the chloroplast is where photosynthesis takes place. The nucleus contains DNA and is the site of transcription.

The Krebs cycle involves aerobic respiration because oxygen is used. Anaerobic respiration involves fermentation because oxygen is lacking and the compound does not enter the Krebs cycle. Glycolysis is the first step in respiration, which precedes the Krebs cycle and is fully anaerobic. Note that oxygen is not directly required for the Krebs cycle (it is not a reactant), however, without oxygen, the electron transport chain will not proceed and thus the Krebs cycle will also be halted.