Introduction to Biomolecules

Abstract

The complexity of even the simplest of life forms, the single cell, cannot be overstated. Nevertheless, from a chemical perspective, cellular components can be segregated into macromolecules (DNA, RNA, proteins, etc.), relatively simple molecules (amino acids, monosaccharides, and lipids), and their precursors: CO₂, H₂O, and NH₃. In general, the macromolecules tend to be polymers of small biomolecules; however, each of these molecules, whether simple or complex, is involved in a myriad of intricate metabolic reactions. A case in point is the monosaccharide glucose which is synthesized from H₂O and CO₂. When degraded to its precursors, it provides the cell with its energy requirements for such diverse processes as macroscopic movement as well as the synthesis of complex macromolecules. In addition, glucose is the fundamental building block of macromolecules such as starch and cellulose. This basic theme, in which the cell uses a simple small molecule in a multitude of processes, is typical of how relatively small biomolecules are used in living systems.