Glycolysis: The Breakdown of Glucose

The first step of glycolysis is the phosphorylation of glucose by hexokinase, which converts glucose into glucose-6-phosphate. This step requires one molecule of ATP.

During glycolysis, two molecules of ATP are consumed and four molecules of ATP are produced, resulting in a net gain of two ATP molecules.

Aldolase catalyzes the cleavage of fructose-1,6-bisphosphate into two three-carbon molecules: glyceraldehyde-3-phosphate and dihydroxyacetone phosphate.

NAD+ is reduced to NADH during glycolysis by glyceraldehyde-3-phosphate dehydrogenase. This reaction generates one molecule of NADH for each molecule of glyceraldehyde-3-phosphate that is oxidized.

The final product of glycolysis is pyruvate, which is a three-carbon molecule. Pyruvate is then converted into acetyl-CoA, which enters the citric acid cycle.

During the conversion of one molecule of glucose to two molecules of pyruvate, two molecules of ATP are produced during glycolysis and two molecules of ATP are produced during the conversion of pyruvate to acetyl-CoA. Therefore, the total ATP yield is 4 molecules of ATP.

Acetyl-CoA is not a substrate for glycolysis. It is a product of glycolysis and enters the citric acid cycle.

Phosphoglucomutase catalyzes the isomerization of glucose-6-phosphate to fructose-6-phosphate. This reaction is necessary for the continuation of glycolysis.

Acetyl-CoA is not a product of glycolysis. It is a product of the citric acid cycle, which occurs after glycolysis.

Glyceraldehyde-3-phosphate dehydrogenase catalyzes the oxidation of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate. This reaction is also known as the Embden-Meyerhof-Parnas pathway.

Decarboxylation of pyruvate is not a step in glycolysis. It is a step in the citric acid cycle, which occurs after glycolysis.

Phosphoglycerate kinase catalyzes the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate. This reaction generates one molecule of ATP for each molecule of 1,3-bisphosphoglycerate that is converted.

Conversion to oxaloacetate is not a fate of pyruvate after glycolysis. Oxaloacetate is a product of the citric acid cycle, which occurs after glycolysis.

Phosphoglyceromutase catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate. This reaction is necessary for the continuation of glycolysis.

FADH2 is not a product of the conversion of one molecule of glucose to two molecules of pyruvate. FADH2 is a product of the citric acid cycle, which occurs after glycolysis.