What is Glycolysis?

Glycolysis is a metabolic process that breaks down sugars to generate energy. This process occurs in two main phases — an energy requiring phase and an energy releasing phase.

To begin with, the glucose first enters the cell's cytoplasm. Next, through a series of enzymatic reactions that require energy in the form of ATP,  glucose is modified into two  molecules of three-carbon glyceraldehyde 3-phosphate.

In the second phase, through multiple enzymatic steps, the two molecules of glyceraldehyde 3-phosphate are converted into 2 molecules of pyruvate, 2 NADH and 4 ATP molecules.

Both these pyruvate molecules are then transported to the mitochondria for entry into the citric acid cycle.