Language English not to Hindi

Glycolysis is the process where one molecule of glucose (a six-carbon compound) is broken down into two molecules of pyruvate (three-carbon compounds). This process takes place in the cytoplasm of the cell.

In this phase, ATP is used to activate glucose.

• Glucose is phosphorylated to form glucose-6-phosphate, using one ATP molecule.
• Glucose-6-phosphate is isomerized to fructose-6-phosphate.
• Fructose-6-phosphate is phosphorylated to form fructose-1,6-bisphosphate, using another ATP molecule.
• Fructose-1,6-bisphosphate is split into two three-carbon molecules: dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P). DHAP can be converted to G3P, resulting in two G3P molecules.

In this phase, energy is produced.

• Each G3P molecule is oxidized, and a phosphate group is added, forming 1,3-bisphosphoglycerate. NAD+ is reduced to NADH in this process.
• A phosphate group from 1,3-bisphosphoglycerate is transferred to ADP, producing ATP and 3-phosphoglycerate (substrate-level phosphorylation).
• 3-phosphoglycerate is isomerized to 2-phosphoglycerate.
• Water is removed from 2-phosphoglycerate, forming phosphoenolpyruvate (PEP).
• A phosphate group from PEP is transferred to ADP, producing another ATP and pyruvate (substrate-level phosphorylation).

At the end of glycolysis, one molecule of glucose yields:

• 2 pyruvate molecules
• 2 net ATP molecules (4 ATP produced, but 2 ATP are used in the investment phase)
• 2 NADH molecules

The pyruvate can then enter further metabolic pathways depending on the presence or absence of oxygen.