When one molecule of glucose undergoes glycolysis, it is broken down to produce energy in the form of ATP (adenosine triphosphate) and other metabolites. Glycolysis is a series of enzymatic reactions that occurs in the cytoplasm of the cell and is the first step in cellular respiration.
Here's a brief overview of the process:
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Initial Investment and Fructose-1,6-bisphosphate Formation: The glucose molecule (a 6-carbon sugar) is phosphorylated using ATP, producing glucose-6-phosphate. This is followed by a series of reactions that ultimately convert glucose-6-phosphate into fructose-1,6-bisphosphate. This phase consumes 2 ATP molecules.
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Cleavage: Fructose-1,6-bisphosphate is then split into two 3-carbon molecules, which are glyceraldehyde-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP). DHAP is quickly converted to G3P.
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Energy Harvesting: Each G3P is converted through a series of reactions into pyruvate, resulting in energy production. During this phase, NAD+ is reduced to NADH, and ATP is produced via substrate-level phosphorylation.
Overall, from one molecule of glucose, glycolysis produces:
- 2 molecules of pyruvate
- 2 molecules of NADH
- 4 molecules of ATP (but since 2 ATP were used in the initial investment phase, the net gain is 2 ATP)
In summary, glycolysis converts one molecule of glucose into two molecules of pyruvate, with a net gain of 2 ATP and 2 NADH, while also producing intermediates for other metabolic pathways.