The ability of all organisms, including microorganisms, to grow and divide is the fundamental underpinning of their continued existence. In the laboratory, the nutrients needed for growth are supplied in the form of growth media.

Microorganisms such as bacteria, yeast, and algae grow by increasing in size, replicating their genetic material and other internal factors such as proteins, manufacturing the required additional cell wall material to enclose the new cell, and finally dividing to form two so-called daughter cells. Vital materials are required by most microbes, including carbon, hydrogen, nitrogen, phosphorus, calcium, cobalt, magnesium, and manganese. Often these elements must be supplied in the growth media, because the microbes cannot manufacture them. Once supplied, however, such elements form the building blocks upon which the microorganism can construct some (but not all) amino aids, proteins, and even the DNA (deoxyribonucleic acid) and ribonucleic...