Catabolic reactions are those that breakdown organic molecules into smaller molecules and release energy. Glycolysis involves the breakdown of glucose into pyruvate, , and . Citric acid cycle is a series of reaction that take acetyl-CoA and oxaloacetate and produce carbon dioxide, , , and . Thus, the Krebs cycle is both catabolic and anabolic. Photosynthesis and protein synthesis are both anabolic reactions. In contrast, while oxidative phosphorylation does produce energy in the form of , is neither catabolic nor anabolic because it simply transfers energy in the form of the electron carrier into  and does breakdown or produce organic molecules.

Per glucose only  is generated in substrate level phosphorylation in glycolysis. Additionally only  is produces per glucose in glycolysis. However the 2 pyruvate that are produced by glycolysis make  and  (along with ) during the citric acid cycle.

Oxygen is neither a product nor reactant in glycolysis. Glycolysis is unique in that it takes place within the cytoplasm of the cell and does not require oxygen. It is an anaerobic reaction that produces pyruvate, NAD, and ATP. Know the products and reactants of glycolysis.

The correct answer to this question is glycolysis.

We can know this if we remember that glycolysis is a ten step anaerobic, not aerobic pathway that uses the 6 carbon sugar known as glucose and converts it to 2 pyruvate molecules. All of the other answers do not use glucose and convert it to pyruvate. 

The correct answer to this question is carbon dioxide.

Carbon dioxide is not produced during glycolysis. Remember in glycolysis one glucose molecule yields 2 pyruvate, 2 ATP, and 2 NADH. Heat is also given off in form of energy as we went over before. Carbon dioxide is involved in other processes.

The correct answer to this question is glycolysis and fermentation.

Glycolysis and fermentation occur in the cytosol of a eukaryotic cell. Chemiosmosis occurs in the inner mitochondrial membrane and thylakoid membranes of chloroplasts in eukaryotes. The citric acid cycle occurs in the mitochondrial matrix. Oxidative phosphorylation occurs in the mitochondria so the answer has to be glycolysis and fermentation

The correct answer to this question is ATP.

Fermentation is the metabolic process that takes place in anaerobic environments to regenerate  for glycolysis. ATP is the main product of cellular respiration and the molecular energy of the cell. The aerobic metabolism results in a very high yield of these energies because it can use oxygen as the final electron acceptor in the electron transport chain.

Anaerobic respiration occurs when there is not enough oxygen necessary for pyruvate to be shunted to the citric acid cycle. In the absence of oxygen, lactate is formed. The purpose of forming lactate is to also regenerate , as  can be used in a cyclical fashion to continue the process of cellular respiration. When oxygen supply returns, the pyruvate will be shunted away from the production of lactate and instead go to the citric acid cycle.

Chemiosmosis is the coupling of the movement of electrons down the electron transport chain with the formation of ATP by utilizing the force of the proton gradient. Think about it this way, the creation of ATP is needed in both photosynthesis and respiration and this is why it is involved in both.

The process of glycolysis indeed occurs in the cytoplasm. Answer 'glycolysis can occur only with oxygen' is incorrect, because glycolysis can actually occur with or without oxygen, due to oxygen playing no role in glycolysis.

Answer 'glycolysis is the first step in anaerobic respiration but not aerobic respiration' is incorrect, because glycolysis is simply the first step in BOTH anaerobic respiration and aerobic respiration.

Answer 'glycolysis leads to the production of 2 ATP, 1 NADH, and 2 pyruvate' is incorrect, because the end product of glycolysis is 2 NADH, not 1 NADH.

Answer 'glycolysis involves the production of G5P or glucose-5-phosphate' is incorrect, because glycolysis involves the production of G6P, not G5P.