Microbiology

Micro is a prefix denoting very small size and is used in the metric system to denote one millionth.
Microbiology means the scientific study of microorganisms (e.g. bacteria, viruses and fungi). Orifinally this was directed towards their effects (e.g. in causing disease and decay), but during the 20th century the enmphasis has shifted to their physiology, biochemistry, and genetics. Microbes are now recognized as important vehicles for the study of biochemical and genetic processes common to all living organisms, and their rapid growth enables their laboratory culture in large numbers for studies in genetics.

Microorganism (microbe) is any organism that can be observed only with the aid of a microscope. Microorganisms include bacteria, viruses, protozoans, and some algae and fungi.

Pathogen means any disease-causing microorganism. Pathogens include viruses, rickettsiae, and many bacteria, fungi and protozoa's.

Virus in microbiology is a particle that is too small to be seen with a light microscope or to be trapped by filters, but is capable of independant metabolism and reproduction within a living cell. Viruses are parasites of animals, plants, and some bacteria. Antibiotics are ineffective against viral diseases but vaccines provide good protection.

Bacteria means a diverse group of ubiquitous microorganisms all of which consist of only a single cell that lacks a distinct nuclear membrane and has a cell wall of a unigue composition.

Fungi is a group of organisms formerly regarded as simple plants lacking chlorophyll but now classified in a separate kingdom, fungi. They can either exist as single cells or make up a multicellular body called a "mycelium", which consists of filaments known as "hyphae".

Algae mean any of the sums of various simple organisms that contain chlorophyll and live in aquatic habitats and in moist locations on the ground. The algal body may be unicellular or multicellular. Formerly regarded as plants, algae are now classified as members of the "Protoctista" species.