What happens in the investment phase of glycolysis?
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Solution
Glycolysis:
It is a series of processes that results in the conversion of six-carbon glucose into two three-carbon keto-acids (pyruvate).
It generates free energy that may be used to synthesise high-energy molecules like ATP and NADH.
Glycolysis is divided into two phases: the energy-investment phase and the energy-yielding phase.
Investment phase of glycolysis:
The glycolysis energy-investment phase involves the investment of two ATP molecules, which leads to the creation of two molecules of glyceraldehyde phosphate.
Hexokinase uses one ATP to convert glucose to glucose-6-phosphate, which is then transformed to ADP.
Phosphoglucose isomerase is an enzyme that transforms glucose-6-phosphate into fructose-6-phosphate.
Phosphofructokinase uses one ATP to convert fructose-6-phosphate to fructose-1,6-bisphosphate, which is then turned into ADP.
Bisphosphate aldolase catalyses the process in which fructose-1,6-bisphosphate is converted into two three-carbon molecules: glyceraldehyde-3-phosphate and dihydroxyacetone phosphate (DHAP).
Triose phosphate isomerase is the enzyme that converts DHAP to glyceraldehyde-3-phosphate. Although this is a reversible process, DHAP is eventually depleted since glycolysis occurs in the following step.