Biochemistry Biochemistry Biochemistry is the study of the chemistry of living organisms. Most chemical reactions in living systems are catalyzed by enzymes, which are proteins.
Many proteins regulate or control biological activity.
Insulin, for example, controls the rate at which sugar is metabolized. O 2 is carried through the bloodstream by hemoglobin and myoglobin. Other proteins transport sugars, amino acids, and ions across the cell membranes. The first line of defense against viruses and bacteria are the antibodies produced by the immune system, which are based on proteins. Carbohydrates are the primary source of food energy for most living systems.