Bacteria

Review Of Related Literature

A. Bacteria

I INTRODUCTION
Bacteria (Greek bakterion, “little staff”), large group of mostly microscopic, unicellular organisms that lack a distinct nucleus and that usually reproduce by cell division.
Bacteria are tiny, most ranging from 1 to 10 micrometres (1 micrometre equals 1/25,000 in), and are extremely variable in the ways they obtain energy and nourishment. They can be found in nearly all environments—from air, soil, water, and ice to hot springs; even the hydrothermal vents on the deep ocean floor are the home of sulphur-metabolizing bacteria. Certain types are found in nearly all food products, and bacteria also occur in various forms of symbiosis with most plants and animals and other kinds of life.
II CLASSIFICATION
In the currently used five-kingdom scheme of classification, bacteria constitute the kingdom Monera, also known as Prokaryotae—organisms in whose cells the nucleus is not enclosed by a me...