any biological molecules are macromolecules, poly mers of high molecular weight assembled from rela tively simple precursors. Proteins, nucleic acids, and
polysaccharides are produced by the polymerization of
relatively small compounds with molecular weights of
500 or less. The number of polymerized units can range
from tens to millions. Synthesis of macromolecules is
a major energy-consuming activity of cells. Macromol ecules themselves may be further assembled into
supramolecular complexes, forming functional units
such as ribosomes. Table 1–2 shows the major classes
of biomolecules in the bacterium E. coli