Yeasts must be viewed through a microscope that magnifies several hundred times. Bacteria can best be seen when studied with a more powerful scope that enlarges 1,000 times. Bacteria, yeasts and molds can be found everywhere. Scientists have gathered them from clouds above mountain tops and in the deepest parts of the ocean. They are present on animals, people and even in the air we breathe.
Microorganisms have a direct impact on our daily lives.
Some are helpful. They aid our bodily processes by helping break down complex foods into simpler substances. Some, called germs, are harmful to us by the role they play in causing diseases. This is a tiny living factory capable of converting simple food substances into energy and new cell material and of reproducing itself. Larger organisms, including people, are composed of billions of cells with many different roles.