During glycolysis, glucose ultimately breaks down into pyruvate and energy; a total of 2 ATP is derived in the process (Glucose + 2 NAD+ + 2 ADP + 2 Pi --> 2 Pyruvate + 2 NADH + 2 H+ + 2 ATP + 2 H2O)
The molecule is the smallest unit of the substance that retains its characteristic properties. The macromolecule is such a unit but is considerably larger than the ordinary molecule.