Bacteria

Bacteria are single-celled mircoorganisms from a a class of organisms called prokaryotes, meaning they have no nucleus. Instead prokaryotes have a loop of DNA within the cytoplasm of their cells. They can be found in virtually any environment on Earth from the deepest part of the ocean to the frozen rocks of Antarctica. They number to an estimated four to six nonillion.PNAS: Prokaryotes: The unseen majority

The ecosystem of our planet relies on bacteria. Nutrients like carbon, nitrogen and sulfur cycle with the help of bacteria. Decomposition of dead and rotting organisms releasing nutrients back into the environment is aided by bacteria. Nitrogen cycles with the help of bacteria. Bacteria convert gaseous nitrogen into nitrates that the plants need.http://www.ucmp.berkeley.edu/bacteria/bacterialh.html

Pathogenic bacteria is what we think of as bad bacteria. It is responsible for some of the worse disease known to mankind. However, these disease causing bacteria are a very small part of the bacteria family. In fact, over 99% of bacteria are helpful.

A bacterial infection can cause humans to get sick. Bacterial infections are spread by close contact with an infected person, contaminated food or water, contaminated surfaces and cuts and abrasions on the skin’s surface. The bacteria can be killed by antibiotics prescribed by a doctor.

Most bacteria can actually be put in three groups. Aerobic bacteria that require oxygen to grow and live. Anaerobic live in deep underwater sediments and can also cause bacterial food poisoning. And facultative anaerobes that can live with or without oxygen.http://www.buzzle.com/articles/helpful-and-harmful-types-of-bacteria.html

Bacteria can also be separated into three groups based on shape. They three shapes are sphere, round and spiral shaped.

Symbiosis is relationship between two species in which both species benefit. For bacteria, the human body provides a home and food where they can live. For the humans, bacteria break down certain hard to digest substances and excrete vitamins. Bacteria also protect the human body from harmful bacteria by crowding them out and using up all of the excess nutrients.