Biological Molecules and Enzymes

A human cell is not a mysterious, indivisible blob of protoplasm; it is an incredibly busy, violently active chemical factory. Every second, millions of precise chemical reactions occur within your cells to keep you breathing, thinking, and reading these words. As a future healthcare professional, your entire career will revolve around manipulating and preserving this chemical factory. When you administer insulin, measure blood pH, or try to bring down a dangerous fever, you are not treating an abstract disease—you are directly intervening in the interactions of microscopic biological molecules. To understand human physiology, pharmacology, and pathology, you must first understand the structural materials that build the body and the molecular machines that do the work.

Every living organism on Earth is constructed from just four major classes of biological macromolecules: carbohydrates, lipids, proteins, and nucleic acids. These molecules are primarily built by linking smaller, repeatable subunits called monomers into long chains called polymers. Let us examine how the structure of each molecule perfectly dictates its function in the human body.