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 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 correct answer to this question is citrate.

Citrate is created when oxaloacetate reacts with acetyl-CoA and then citrate is converted to isocitrate, which then donates electrons and a hydrogen to . Malate is not involved in this process but it is an intermediate of the citric acid cycle. Glycinate is just a mineral supplement, and nitrate and oxalate have no role in the citric acid 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.

In cellular respiration, oxygen is the final electron acceptor. Oxygen accepts the electrons after they have passed through the electron transport chain and ATPase, the enzyme responsible for creating high-energy ATP molecules. Just remember cellular respiration—respiration means breathing, and you cannot breathe without oxygen.

Oxygen is the final electron acceptor in the electron transport chain, showing the need for aerobic conditions to undergo such a process. ATP is produced as a product of the electron transport chain, while glucose and CO₂ play a role in earlier processes of cellular respiration.

Glyceraldehyde-3-phosphate is converted to 1,3-bisphosphoglycerate, and one NADH is also produced during that step. NADH enters the electron transport chain, and is therefore worth ATP. Normally, an NADH is worth about 2.5 ATP; however, an NADH produced in glycolysis is only worth 1.5 ATP because it costs 1 ATP to move that NADH from the cytoplasm into the mitochondria. So, in this first step, we have a total of 1.5 ATP.

As the molecule continues on its path to become pyruvate, it will also produce two ATP directly; therefore, we have a net total of 3.5 potential ATP.  

Oxygen is the final electron acceptor in the electron transport chain, which allows for oxidative phosphorylation. Without oxygen, the electrons will be backed up, eventually causing the electron transport chain to halt. This will cause the products of glycolysis to go through fermentation instead of going to the citric acid cycle. Without oxygen, oxidative phosphorylation (the electron transport chain) is impossible, but substrate-level phosphorylation (glycolysis) continues.

Cellular respiration typically follows three steps, under aerobic conditions. Glycolysis generates NADH and converts glucose to pyruvate, while producing small amounts of ATP through substrate-level phosphorylation. The citric acids cycle, or Krebs cycle, uses pyruvate to generate more NADH and FADH₂. These NADH and FADH₂ molecules donate electrons to the electron transport chain, which are used to pump protons into the intermembrane space of the mitochondrion. The protons in the intermembrane space then flow through ATP synthase to generate large amounts of ATP via oxidative phosphorylation.

Oxygen serves as the terminal electron acceptor for the electron transport chain. Electrons are donated by NADH molecules and passed through several different proteins to generate the proton gradient in the intermembrane space. Upon reaching the final protein, the electron is bonded to an oxygen molecule to create water. Without oxygen, there would be nowhere for the electrons to go after being pumped through the electron transport chain, and aerobic cellular respiration would be impossible.