Anatomy of the groupO Archaebacteria are a type of prokaryote, that is, a unicellular organism without a cell nucleus.O They make up the kingdom Archae, one of the main kingdoms of life.O They have similarities to both normal bacteria and the larger eukaryotes.O They are like unicellular prokaryotes,but their creation is similar to that of the more complex eukaryotes.O Archaebacteria were not recognized as a distinct form of life from bacteria until 1977, when Carl Woese and George Fox determined this through RNA studies.O Archaebacteria are non-pathogenic, living in and around other organisms but not infecting them.O Kingdom Archae has a close relationship to the kingdom Eukarya, the two sharing many genetic trees and common traits.O One of the first places Archae were discovered was at the boiling hot springs in Yellowstone National Park.
Characteristics:O Archae are very similar to bacteria.O Forms vary mainly in canes, coconuts and spirillar.O They reproduce mainly by fussion , as most as bacteriaO They have abundant proteins of histone and the DNA is packaged in the form of nucleosomes.O They contain large amounts of non-polar lipids.O The global organization of the cell membrane is similar to the one found in bacteria and eukaryotes.O We can think of Archaea as a link lost between bacteria and eukariote.O A group of unicellular microorganisms of the archae domainO They are prokaryotes that lack a cell nucleus or any other organelle within the cell.O They present many differences in their biochemistry with respect to other forms of life.O They habitats include in the geysers of Yellowstone Park and also volcanoes they re adapted to hot weathers.O The evolutionary relationship between archae and eukaryotes remain unclear.
Physiology:O Archaea exhibit a great variety of chemical reactions in their metabolism and use many sources of energy.O These reactions are classified into nutritional groups, depending on energy and carbon sources,some archaea obtain energy from inorganic compounds such as sulfur or ammonia.O These include nitrifiers, methanogens and anaerobic methane oxidise rs.O One compound acts as an electron donor and one as an electron acceptorO . Other groups of archaea use sunlight as a source of energy. However, oxygen–generating photosynthesis does not occur in any of these organisms.
MotilityO Archaea have measured between 0.1 mm and over 15 mm and come in various forms.O They”re found in hypersaline pools a kind of square and flat called "Haloquadra walsbyi”O They”re unusual shapes is probably maintained by both the cell wall as a prokaryotic cytoskeleton.O Archaea cells related proteins are identified with cytoskeletal components and filaments.O Most archaea have a cell wall, the exceptions being Thermoplasma and Ferroplasma.O In most archaea, the wall comprises surface proteins which form a "S layer" which is a rigid assembly of protein molecules that cover the exterior of the cell as a mesh.O This can serve as a barrier, preventing macromolecules coming into contact with the cell membrane.O They also have flagella, which function in a manner similar to bacterial flagella
DIVERSITYO Archae are group of microbes that form one of three main domains of life.O They also are the most abundant and active microbial component in some enviroment.O Comparison of small subunit ribosomal RNA (16S rRNA) gene sequences and other cellular characteristics revealed that Archaea are a distinct group of microbes and one of three domains of life on Earth.O The majority of archaeal diversity is composed of two kingdoms: the Crenarchaeota and Euryarchaeota.O Most of the cultured archaea are ‘extremophiles’, or organisms that are adapted to living under extreme environmental conditions.O The common ecological factor among the Archaea is their propensity to thrive under conditions of chronic energy stress.O The ‘uncultured majority’ refers to the abundant, widespread, and highly diverse groups of archaea that currently lack cultured isolates.O The metabolic functions of some uncultured archaea have been revealed by combining molecular, biochemical and geochemical techniques.
ClassificationO The classification of archaea has been very controversial, most species of arable and well researched archaea are members of two main phyla: Euryarchaeota and Crenarchaeota.O The classification of archaea into species is also controversial and complicated.O They are asexual and have a high level of horizontal gene transfer between lineages.O Nanoarchaeum equitans was discovered in 2003, has been given its own phylumO Archaea are classified into nutritional groups, the source of energy and carbon.O Some archaea obtain energy from inorganic compounds such as sulfur or ammoniaO Other groups of archaea use sunlight as an energy source such as algae, protists and bacteria.
DistributionO Archaea exist in a variety of habitatsO Archaea are important part of global ecosystems and may represent up to 20% of the total biomass on Earth.O Lots of Archaea are extremophilesO Some archaea survive high temperatures, often above 100 C, as the ones in the geysers.O Others live in very cold habitats and others in highly saline water, acid or alkaline.O Archaea are already living in a much more soft and moist as sewers, oceans and soil.O Extremophilic archaea are members of major physiological four groups: halophiles, thermophiles, alkaliphiles and acidophilus.O Halophiles live in extremely salty, like salt lakes, and begin to outperform their bacterial counterparts at salinities greater than 20-25% .68O Thermophiles, thrive at temperatures above 45 C, in places like hot springs.O Alkaliphiles and acidophilus, which exist in very acidic or alkaline conditions
PROS & CONSO Archaea are among Earth systems that recycle elements like carbon, nitrogen and sulfur in the various habitats of each ecosystem.O Vital for the normal functioning of ecosystems, archaea may also contribute to the changes that humans cause to the environment, and even cause pollution.O Archaea perform multiple steps of the nitrogen cycle, which includes both disimilatorias reactions that remove nitrogen from ecosystemsO Archaea that grow and oxidize sulfur compounds are important because they release this element from rocks, making it available for other organisms.O archaea that do this, can cause environmental damage, they produce sulfuric acid as a waste product, and the growth of these organisms in abandoned mines can cause acid mine drainage.O In the carbon cycle, archaea are relevant as producers of methane.O Methane is a greenhouse gas more abundant in the Earths atmosphere, accounting for 18% of total.114 is a greenhouse gas 25 times more potent than carbon dioxide.O These archaea contribute to global emissions of greenhouse gases and global warming.O Archaea, particularly resistant to high temperatures or extremes of acidity and alkalinity, are an important source of enzymes that can function under these harsh conditions.
PROS & CONSO These enzymes have a wide range of applications as they have revolutionized molecular biology by allowing the reaction using the polymerase chain as simple and fast method for cloning DNA.O Furthermore, they could allow the creation of new selectable markers for use in molecular biology.O The discovery of new substances depends on the recovery of these organisms in the environment and their culture.