In glycolysis, glycerol enters central metabolism as what molecule?

Glycerol enters central metabolism as PGAL (phosphoglyceraldehyde), also known as glyceraldehyde-3-phosphate. This occurs through a series of biochemical reactions where glycerol is first converted into glycerol-3-phosphate by the enzyme glycerol kinase. Then, glycerol-3-phosphate undergoes further conversion into dihydroxyacetone phosphate (DHAP), which is readily interconverted with PGAL.

In glycolysis, PGAL plays a crucial role as it is one of the intermediates that eventually leads to the production of pyruvate. The conversion of glycerol into PGAL allows the body to utilize glycerol derived from triglycerides and other lipid sources for energy production. This integration showcases how fats can be metabolically linked to carbohydrate metabolism, underscoring the versatility of fuel sources that the body can use.

Other options do not accurately represent the direct entry of glycerol into metabolic pathways. Acetyl-CoA is a key crossroads in metabolism but primarily derives from the breakdown of carbohydrates and fats, including pyruvate produced from glycolysis. While pyruvate is an end product of glycolysis, it is not the direct metabolite that glycerol transforms into. Fatty acids,