Bacteria

Bacteria (common noun bacteria, singular bacterium) are a type of biological cell.

Organisms can be classified as unicellular (consisting of a single cell; including bacteria) or multicellular (including plants and animals).

Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals.

Perhaps the most obvious structural characteristic of bacteria is (with some exceptions) their small size.

Most bacteria have not been characterised, and only about 27 percent of the bacterial phyla have species that can be grown in the laboratory (specifically unculturable phyla, known as candidate phyla, make up 103 out of approximately 142 known phyla).

The bacterial phyla are the major lineages, known as phyla or divisions, of the domain Bacteria.

Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals.

Spiral bacteria, bacteria of spiral (helical) shape, form the third major morphological category of prokaryotes along with the rod-shaped bacilli and round cocci.

Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals.

A bacillus (plural bacilli) or bacilliform bacterium is a rod-shaped bacterium or archaeon.

They constitute a large domain of prokaryotic microorganisms.

Of the three domains of life identified by Carl Woese, all of the Archaea and Bacteria are microorganisms.

Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals.

A coccus (plural cocci) is any bacterium or archaeon that has a spherical, ovoid, or generally round shape.

Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of the earth's crust.

The subsurface accounts for about 90% of the biomass in two domains of life, Archaea and Bacteria, and 15% of the total for the biosphere.

Virtually all animal life on earth is dependent on bacteria for their survival as only bacteria and some archea possess the genes and enzymes necessary to synthesize vitamin B 12, also known as cobalamin, and provide it through the food chain.

The only organisms to produce vitamin B 12 are certain bacteria, and archaea.

However, several species of bacteria are pathogenic and cause infectious diseases, including cholera, syphilis, anthrax, leprosy, and bubonic plague.

Pathogenic bacteria are bacteria that can cause disease.

However, several species of bacteria are pathogenic and cause infectious diseases, including cholera, syphilis, anthrax, leprosy, and bubonic plague.

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum subspecies pallidum.

However, several species of bacteria are pathogenic and cause infectious diseases, including cholera, syphilis, anthrax, leprosy, and bubonic plague.

Cholera is an infection of the small intestine by some strains of the bacterium Vibrio cholerae.

The vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial, particularly in the gut flora.

Probiotics are considered generally safe to consume, but may cause bacteria-host interactions and unwanted side effects in rare cases.

However, several species of bacteria are pathogenic and cause infectious diseases, including cholera, syphilis, anthrax, leprosy, and bubonic plague.

Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria Mycobacterium leprae or Mycobacterium lepromatosis.

The most common fatal bacterial diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year, mostly in sub-Saharan Africa.

Tuberculosis (TB) is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria.

Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere.

Nitrogen fixation is carried out naturally in soil by microorganisms termed diazotrophs that include bacteria such as Azotobacter and archaea.

In developed countries, antibiotics are used to treat bacterial infections and are also used in farming, making antibiotic resistance a growing problem.

An antibiotic is a type of antimicrobial substance active against bacteria and is the most important type of antibacterial agent for fighting bacterial infections.

The vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial, particularly in the gut flora.

Even simple unicellular organisms such as bacteria possess a rudimentary immune system in the form of enzymes that protect against bacteriophage infections.

In developed countries, antibiotics are used to treat bacterial infections and are also used in farming, making antibiotic resistance a growing problem.

The term antibiotic resistance (AR or ABR) is a subset of AMR, as it applies only to bacteria becoming resistant to antibiotics.

The study of bacteria is known as bacteriology, a branch of microbiology.

Eukaryotic microorganisms possess membrane-bound organelles and include fungi and protists, whereas prokaryotic organisms—all of which are microorganisms—are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea.

In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy.

Some bacteria were found living in the cold and dark in a lake buried a half-mile deep under the ice in Antarctica, and in the Marianas Trench, the deepest place in Earth's oceans.

In industry, bacteria are important in sewage treatment and the breakdown of oil spills, the production of cheese and yogurt through fermentation, the recovery of gold, palladium, copper and other metals in the mining sector, as well as in biotechnology, and the manufacture of antibiotics and other chemicals.

Yogurt ( or ; from yoğurt), also spelled yoghurt, yogourt or yoghourt, is a food produced by bacterial fermentation of milk.

The largest number exist in the gut flora, and a large number on the skin.

Intestinal bacteria also play a role in synthesizing vitamin B and vitamin K as well as metabolizing bile acids, sterols, and xenobiotics.

They constitute a large domain of prokaryotic microorganisms.

According to this system, the tree of life consists of three domains: Archaea, Bacteria, and Eukarya.

The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process.

Decomposition begins at the moment of death, caused by two factors: 1.) autolysis, the breaking down of tissues by the body's own internal chemicals and enzymes, and 2.) putrefaction, the breakdown of tissues by bacteria.