Cleavage in glycolysis refers to the splitting of the six-carbon molecule (fructose-1,6-bisphosphate) into two three-carbon molecules.
Here's a more detailed explanation:
Glycolysis is a metabolic pathway that breaks down glucose into pyruvate. This process can be divided into two main phases: the energy-investment phase and the energy-payoff phase. Cleavage occurs during the energy-investment phase.
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Energy-Investment Phase: In this initial phase, the glucose molecule undergoes phosphorylation (addition of phosphate groups) and is converted into fructose-1,6-bisphosphate. This step requires the input of two ATP molecules.
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Cleavage: The six-carbon fructose-1,6-bisphosphate molecule is then split (cleaved) into two three-carbon molecules:
- Dihydroxyacetone phosphate (DHAP)
- Glyceraldehyde-3-phosphate (G3P)
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Isomerization: DHAP is then isomerized (converted) into another molecule of G3P. As a result, each original glucose molecule ultimately yields two molecules of G3P.
Therefore, the "cleavage" step is essential because it sets the stage for the energy-payoff phase where ATP and NADH are produced from the two three-carbon molecules. This splitting process ensures that the initial glucose molecule is processed in a manageable and efficient manner.
