Glycolysis

Phosphorylation:

•  one ATP is hydrolysed and the phosphate group attaches to glucose at carbon 6.
• Glucose 6-phosphate is changed to fructose 6-phosphate.
• Another ATP is hydrolysedand the phosphate group attaches to fructose 6-phosphate at carbon 1.
• The energy from ATP activates the hexose sugar, it is known as hexose 1,6  bisphosphate.

Splitting of hexose 1,6 bisphosphate:

• Hexose 1,6 bisphosphate is split into 2 molecules of triose phosphate

Oxidation of Triose Phosphate:

• two hydrogen atoms are removed from each triose phosphate molecule (involves dehydrogenase enzymes)
• NAD combines with the hydrogen to become reduced NAD
• two molecules of ATP are formed (substrate-level phosphorylation)

Conversion of Triose Phosphate to Pyruvate

• Triose phosphate is converted to an intermediate compound, then to pyruvate.
• two molecules of ATP are formed (substrate level phosphorylation)

Products:

net gain of 2ATP (total 4 ATP) , 2 reduced NAD, 2 pyruvate.