Probably the best known microorganisms, molds are widely distributed in nature and grow under a variety of conditions in which air and moisture are present. They are also plants and a part of the fungi family. Nearly everyone has seen mold growth on damp clothing and old shoes. So, many may find it hard to believe that mold is a microorganism. However, the mold we see with the naked eye is actually a colony of millions of mold cells growing together.
Molds vary in appearance.
Unlike bacteria, molds are made up of more than one cell. Vegetative cells sustain the organism by taking in food substances for energy and the production of new cell material. Unlike bacterial spores, mold spores are the source of new mold organisms. Bacterial spores generally form only when environmental conditions are unfavorable. Molds produce a stem consisting of several cells.