Bacteria are tiny, single-celled organisms which can perform all seven life processes, despite their minuscule size. These vital processes include: movement, respiration, sensitivity, growth, respiration, excretion and nutrition.
Bacterium contain cytoplasm within their cellular membranes, just like animal cells, yet they are also enclosed by cell walls, similar to plant cells. Bacteria are unique because unlike plants or animals, these cells lack a true nucleus. Their genetic information is contained within an irregularly shaped nucleoid, which floats freely within the cytoplasm.
Bacteria is usually known for causing sickness, although not all bacteria is actually harmful. One example of healthy bacteria is those present in the digestive system. Gut bacteria help to break down foods and prevent illness such as diabetes, obesity, and certain forms of cancer. Bacteria are an important part of every ecosystem, even in harsh Arctic environments.
Although all bacteria are small, lack a nucleus, and belong to the kingdom Monera, they are classified into two groups that differ in just about every way. These two groups are the Archaea (Archaeobacteria) and the Eubacteria (true bacteria).
To learn the biological differences between these two groups, please browse below.
Although species of Archaea resemble Eubacteria under the microscope, they are very distinctive, both biochemically and genetically. This group includes inhabitants of extreme environments such as thermal vents in the ocean floor and areas of high salinity, acidity, and alkalinity. They are also found in the digestive tracts of marine life, as well as in the anoxic layer of mud at the bottom of the ocean. Recent findings suggest that Archaea also live in favourable environments, such as the upper water column in both temperate and frigid oceans. Their ability to withstand extreme environments makes the Archaeobacteria a prime candidate to inhabit the harsh conditions of Canada's Arctic.
Eubacteria are simple unicellular organisms. Although they are among the smallest organisms, ranging from 0.3 to 2.0 microns in diameter, they have colonized every area of the planet. Some live in animal intestines, where they aid in digestive processes and vitamin production, while others live on skin. In soil and water, Eubacteria play important roles in the cycling of carbon, nitrogen, sulphur, and other elements. Many Eubacteria are important decomposers of dead organic material and animal waste, but other groups are capable of photosynthesis. Unfortunately, some Eubacteria also cause disease, infection, and produce toxins.
To explore the different types of Eubacteria, please browse below.
- Blue-Green Algae (Cyanobacteria)
- Gram-Negative Rods and Cocci
- Gram-Positive Cocci
- Gram-Positive Rods
- Photosynthetic Eubacteria
- "What are Bacteria?". BBC Bitesize. Retrieved 9 July 2019.