Read about the Domain Archaea and choose one interesting species to research. Tr
ID: 148265 • Letter: R
Question
Read about the Domain Archaea and choose one interesting species to research. Try not to duplicate a species chosen by a classmate, if possible. This is unavoidable if you submit posts simultaneously; however, please scan the discussion area before choosing your species to try to avoid duplication. Find a well-written interesting outside source (scientific journal article, website, etc.) about your species. Present to your classmates a summary of the life history of the species and explain in detail why it was determined to be a member of the Domain Archaea rather than the Domain Bacteria. Remember to include a link to your outside source to enable your classmates to access it. (please include the link and don;t plagiarize)
Explanation / Answer
The Archaea domain contains single-celled organisms called archaea. They were earlier mistaken as bacteria because of their similarity in apperance. However, several studies have shown that archaea are different from bacteria in their cell wall composition, membrane composition and rRNA type. Archaea live in extreme environmental conditions. This includes within hydrothermal vents, acidic springs, and under Arctic ice. Archaea are divided into three main phyla: Crenarchaeota, Euryarchaeota, and Korarchaeota.
The Archaea specie I have selected is Halobacterium salinarum.
Classification:
Domain: Archaea
Phylum: Euryarchaeota
Class: Halobacteria
Order: Halobacteriales
Family: Halobacteriaceae
Genus: Halobacterium
Species: Halobacterium salinarum
Characteristics:
They a single celled microorganisms. Rod shaped, motile and halophilic (live in high salt concentration environment). They have a higher salt concentration and hence their proteins do not function in low salt concentration environments. They undergo aerobic respiration. They are present in two colours-purple and red, based on the protein present. The purple Halobacteria is caused by a light sensitive protein called bacteriarhodopsin, which uses sunlight to drive protons out of the cell, giving the cell energy. Halobacterium is a flagellated organism which shows (chemo)tactic behaviour. Besides being able to detect essential amino acids (chemotaxis) and osmotically active compounds (osmotaxis), it can respond to light (phototaxis) and can sense oxygen (aerotaxis). They reproduce by binary fission.
Halobacterium has a chromosome of 2 Mb having 68% GC and a number of megaplasmids with an average of 58% GC.
the cell membrane is single lipid bilayer membrane surrounded by an S-layer made from the cell-surface glycoprotein.
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