Bacteria

Definition - What does Bacteria mean?

Bacteria constitute a huge domain of prokaryotic microorganisms. Their cell structure is less complex than that of other organisms because they lack a membrane or nucleus bound organelles and they are single-celled. Their genetic information is present in their single DNA chromosome.

A number of bacteria have an extra line of the genetic material referred to as a plasmid, which is frequently composed of genes that give such bacteria an advantage over the others.

The singular term for bacteria is bacterium.

MaximumYield explains Bacteria

Bacteria are categorized into five groups depending on their shapes:

  1. Comma (vibrio)
  2. Spiral (spirilla)
  3. Rod (bacilli)
  4. Spherical (cocci)
  5. Corkscrew (spirochaetes)

Bacteria can exist as single cells, in chains or clusters, or pairs. Bacteria are highly significant in recycling nutrients, with numerous parts of the nutrient cycle dependent on these microscopic organisms. Such stages include putrefaction and the fixation of nitrogen from the atmosphere. In biological communities that surround cold seeps and hydrothermal vents, bacteria convert dissolved compounds like methane and hydrogen sulfide to the energy needed to sustain life in these communities.

There are normally a million bacterial cells in a milliliter of fresh water and 40 million of such organisms in a gram of soil. It is said that the biomass of bacteria on Earth exceeds that of all animals and plants combined. The human flora (the skin and the gut) contains approximately ten times as many bacteria as there are human cells. However, the huge number of bacteria in the human body is considered harmless and cannot overpower the immune system.

Commercially, bacteria are used in the breakdown of oil spills and treatment of sewage, recovery of metals such as copper, palladium, and gold in mining, and production of cheese and yogurt by a process known as fermentation.

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