DocuWatch on Facebook
Art America Britain History Science Societies War Shop
DocuWatch

Biology - Bacteria

« BioBricks - Building Blocks of Life

Biology - Flagellates And Amoebas »

Description

From Wikipedia

Biology - Bacteria

The bacteria
(en-us-bacteria.ogg ; singular: bacterium) are a large group of unicellular, prokaryote, microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. Bacteria are ubiquitous in every habitat on Earth, growing in soil, acidic hot springs, radioactive waste, water, and deep in the Earth's crust, as well as in organic matter and the live bodies of plants and animals. There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water; in all, there are approximately five nonillion (5×1030) bacteria on Earth, forming much of the world's biomass. Bacteria are vital in recycling nutrients, with many steps in nutrient cycles depending on these organisms, such as the fixation of nitrogen from the atmosphere and putrefaction. However, most bacteria have not been characterized, and only about half of the phyla of bacteria have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology.

There are approximately ten times as many bacterial cells in the human flora of bacteria as there are human cells in the body, with large numbers of bacteria on the skin and as gut flora. The vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, and a few are beneficial. However, a few species of bacteria are pathogenic and cause infectious diseases, including cholera, syphilis, anthrax, leprosy and bubonic plague. The most common fatal bacterial diseases are respiratory infections, with tuberculosis alone killing about 2 million people a year, mostly in sub-Saharan Africa. In developed countries, antibiotics are used to treat bacterial infections and in agriculture, so antibiotic resistance is becoming common. In industry, bacteria are important in sewage treatment, the production of cheese and yoghurt through fermentation, as well as in biotechnology, and the manufacture of antibiotics and other chemicals.

Once regarded as plants constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two very different groups of organisms that evolved independently from an ancient common ancestor. These evolutionary domains are called Bacteria and Archaea.

Tags

 

Other videos in channel "All videos":

 Aristotle's Lagoon Aristotle's Lagoon  Atoms Old and New Atoms Old and New  Metamorphosis - Amphibian Nature Documentary Metamorphosis - Amphibian Nature Documentary
 Richard Feynman Richard Feynman A Brilliant Madness A Brilliant Madness
A Decade Of The Human Genome A Decade Of The Human Genome A Mathematical Mystery Tour - (1984) A Mathematical Mystery Tour - (1984) A Vital Poison (1993) A Vital Poison (1993)
Absolute Zero Absolute Zero African Sleeping Sickness (1988) African Sleeping Sickness (1988)
Aircrash Burning Issue - (1987) Aircrash Burning Issue - (1987) Alergic To The 20th Century - (1993) Alergic To The 20th Century - (1993) Alien Contact - (2003) Alien Contact - (2003)
Aliens from Mars - (1996) Aliens from Mars - (1996) Alternative Medicine - Critical Eye Alternative Medicine - Critical Eye An Expensive Theology - (1992) An Expensive Theology - (1992)
Anasthetics Anasthetics Anatomy of an Inventor - (1989) Anatomy of an Inventor - (1989) Ape Genius Ape Genius
Ape To Man Ape To Man Ape-man Ape-man Archimedes Secret - (2002) Archimedes Secret - (2002)
Are We Alone in the Universe Are We Alone in the Universe Are We Still Evolving? Are We Still Evolving? Arithmetic, Population And Energy Arithmetic, Population And Energy
Assault on the Male Assault on the Male Asteroids - The Good, The Bad, The Ugly Asteroids - The Good, The Bad, The Ugly Astrology, Behind The Horoscope - (1980) Astrology, Behind The Horoscope - (1980)
Atom Atom Atoms and their Electrons Atoms and their Electrons Attack of the Sun Attack of the Sun
Awakening the Frozen Addicts (1993) Awakening the Frozen Addicts (1993) Back From The Dead - (2010) Back From The Dead - (2010) Basic Math Basic Math
Battle for Earth Battle for Earth Battle Of The Brains - (2007) Battle Of The Brains - (2007) Beautiful Equations Beautiful Equations
Bermuda Triangle Bermuda Triangle Better Mind the Computer - (1993) Better Mind the Computer - (1993) Beyond The Big Bang Beyond The Big Bang
Beyond the Milky Way Beyond the Milky Way BioBricks - Building Blocks of Life BioBricks - Building Blocks of Life Biology - Bacteria Biology - Bacteria
Biology - Flagellates And Amoebas Biology - Flagellates And Amoebas Biology - Fungi Biology - Fungi Biology - Plants Biology - Plants
Biology - Structure And Function Biology - Structure And Function Biology at War A Plague in the Wind - (1984) Biology at War A Plague in the Wind - (1984) Biology-Science of Life 01 - 10 Biology-Science of Life 01 - 10
Biology-Science of Life 11 - 20 Biology-Science of Life 11 - 20 Biology-Science of Life 21 - 25 Biology-Science of Life 21 - 25 Biosphere 2 Biosphere 2
Blood and Guts - A History of Surgery Blood and Guts - A History of Surgery Botany of Desire Botany of Desire Brains and Babies - (2013) Brains and Babies - (2013)
Bruno Bettleheim Bruno Bettleheim Bye Bye Planet Pluto Bye Bye Planet Pluto Cancer at Bay - (1988) Cancer at Bay - (1988)
Cannabis - (2009) Cannabis - (2009)    
See 481 further videos in this channel: All videos
Video channels
Videos in this channel
Adsense
Featured
Featured
Featured
Featured
Featured
Featured