Nicotinamide Adenine Dinucleotide (NAD)

and Nicotinamide Adenine Dinucleotide Phosphate (NADP)

Nicotinamide adenine dinucleotide (NAD) and its relative nicotinamide adenine dinucleotide phosphate (NADP) are two of the most important coenzymes in the cell. NADP is simply NAD with a third phosphate group attached as shown at the bottom of the figure.

Because of the positive charge on the nitrogen atom in the nicotinamide ring (upper right), the oxidized forms of these important redox


Glycolysis is the anaerobic catabolism of glucose.

  • It occurs in virtually all cells.
  • In eukaryotes, it occurs in the cytosol.
  • It converts a molecule of glucose into 2 molecules of pyruvic acid.
  • C6H12O6 + 2NAD+ -> 2C3H4O3 + 2NADH + 2H+
  • The free energy stored in 2 molecules of pyruvic acid is somewhat less than that in the original glucose molecule.
  • Some of this difference is captured in 2 molecules of ATP.

The Fates of Pyruvic Acid

In Yeast

  • Pyruvic acid is

Cellular Respiration

Index to this page

Cellular respiration is the process of oxidizing food molecules, like glucose, to carbon dioxide and water.


C6H12O6 + 6O2 + 6H2O → 12H2O + 6 CO2

The energy released is trapped in the form of ATP for use by all the energy-consuming activities of the cell.

The process occurs in