During glycolysis, one molecule of glucose (C6H12O6) undergoes a series of enzymatic reactions to be broken down into two molecules of pyruvate (C3H4O3). The process occurs in the cytoplasm of the cell and involves several key steps, leading to the production of energy in the form of ATP and NADH. Here's a summary of what is processed during glycolysis:
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Breakdown of Glucose: One molecule of glucose is split into two molecules of glyceraldehyde-3-phosphate (G3P), which are three-carbon molecules.
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ATP Investment and Generation:
- Initially, two ATP molecules are consumed in the early steps of glycolysis to phosphorylate glucose and its derivatives.
- Later in the pathway, four ATP molecules are produced through substrate-level phosphorylation. Thus, the net gain of ATP from one molecule of glucose is two ATP molecules.
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NADH Production: During the conversion of G3P to pyruvate, two molecules of NAD+ are reduced to two molecules of NADH. This is important for later stages of cellular respiration, particularly in anaerobic conditions or fermentation.
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Pyruvate Formation: The process results in the formation of two molecules of pyruvate.
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Other Byproducts: Some intermediates of the glycolytic pathway can enter other metabolic pathways, influencing processes like amino acid synthesis and the citric acid cycle (if oxygen is present for further aerobic respiration).
In summary, from one molecule of glucose, glycolysis produces:
- 2 molecules of pyruvate
- 2 net molecules of ATP (4 produced - 2 consumed)
- 2 molecules of NADH