Archaea Domain - Extreme Microscopic Organisms

Archaea Domain - Extreme Microscopic Organisms What Are Archaea? Archaea are a group of microscopic organisms that were discovered in the early 1970s. Like bacteria, they are single-celled prokaryotes. Archaeans were originally thought to be bacteria until DNA analysis showed that they are different organisms. In fact, they are so different that the discovery prompted scientists to come up with a new system for classifying life.  There is still much about archaeans that is not known. What we do know is that many are extreme organisms that live and thrive under some of the most extreme conditions, such as extremely hot, acidic, or alkaline environments. Key Takeaways Originally thought to be bacteria, Archaea are a separate group of microscopic organisms discovered in the 1970s. Archaeans are single-celled prokaryotes.Archaeans are extreme organisms. They can survive and even thrive under some of the most difficult conditions on planet Earth like very hot, extremely acidic, or very alkaline environments.Similar to bacteria, Archaeans have a number of different shapes. Cocci (round), bacilli (rod-shaped), and irregular are some examples.Archaeans possess the typical prokaryotic cell anatomy that includes plasmid DNA, a cell wall, a cell membrane, a cytoplasmic area, and ribosomes. Some archaeans can also have flagella. Archaea Cells Archaeans are extremely small microbes that must be viewed under an electron microscope to identify their characteristics. Like bacteria, they come in a variety of shapes including cocci (round), bacilli (rod-shaped), and irregular shapes. Archaeans have a typical prokaryotic cell anatomy:  plasmid DNA, cell wall, cell membrane, cytoplasm, and ribosomes. Some archaeans also have long, whip-like protrusions called flagella, which aid in movement. Archaea Domain Organisms are now classified into three domains and six kingdoms. The domains include Eukaryota, Eubacteria, and Archaea. Under the archaea domain, there are three main divisions or phyla. They are: Crenarchaeota, Euryarchaeota, and Korarchaeota. Crenarchaeota Crenarchaeota consist mostly of hyperthermophiles and thermoacidophiles. Hyperthermophilic microorganisms live in extremely hot or cold environments. Thermoacidophiles are microscopic organisms that live in extremely hot and acidic environments. Their habitats have a pH between 5 and 1. You would find these organisms in hydrothermal vents and hot springs. Crenarchaeota Species Examples of Crenarchaeotans include: Sulfolobus acidocaldarius - found near volcanic environments in hot, acidic springs containing sulfur.Pyrolobus fumarii - live in temperatures between 90 and 113 degrees Celsius. Euryarchaeota Euryarchaeota organisms consist mostly of extreme halophiles and methanogens. Extreme halophilic organisms live in salty habitats. They need salty environments to survive. You would find these organisms in salt lakes or areas where sea water has evaporated.Methanogens require oxygen free (anaerobic) conditions in order to survive. They produce methane gas as a byproduct of metabolism. You would find these organisms in environments such as swamps, wetlands, ice lakes, the guts of animals (cow, deer, humans), and in sewage. Euryarchaeota Species Examples of Euryarchaeotans include: Halobacterium - include several species of halophilic organisms that are found in salt lakes and high saline ocean environments.Methanococcus - Methanococcus jannaschii was the first genetically sequenced Archaean. This methanogen lives near hydrothermal vents.Methanococcoides burtonii - these psychrophilic (cold-loving) methanogens were discovered in Antarctica and can survive extremely cold temperatures. Korarchaeota Korarchaeota organisms are thought to be very primitive life forms. Little is currently known about the major characteristics of these organisms. We do know that they are thermophilic and have been found in hot springs and obsidian pools. Archaea Phylogeny Archaea are interesting organisms in that they have genes that are similar to both bacteria and eukaryotes.  Phylogenetically speaking, archaea and bacteria are thought to have developed separately from a common ancestor.  Eukaryotes are believed to have branched off from archaeans millions of years later. This suggests that archaeans are more closely related to eukayotes than bacteria. Interesting Archaeans Facts While Archaeans are very similar to bacteria, they are also much different. Unlike some types of bacteria, archaeans can not perform photosynthesis. Similarly, they cannot produce spores. Archaeans are extremophiles. They can live in places where most other life forms cannot. They can be found in extremely high temperature environments as well as extremely low temperature environments. Archaeans are a natural part of human microbiota. At present, pathogenic archaeans have not been identified. Scientists assume that they do not exist.

The French Verb Conjugations of Chauffer (to Heat)

The French Verb Conjugations of Chauffer (to Heat) In French,  the verb  chauffer  means  to heat. This can easily be confused with chauffeur as in driver. To keep it straight, think of the verb more like a chaffing dish, meaning a heated food serving platter you often see at buffets or banquets. Conjugating the French Verb  Chauffer​ As with all French verbs, we need to conjugate  chauffer  in order for it to mean heating or heated. The -ing and -ed endings are English conjugations and they are universal to the subject. Yet, in French, we must match the verb with the tense as well as the subject: the endings for we is different than the endings for I. While verb conjugations are challenging  for many French students, those that end in -er  often follow a prescribed pattern.  Chauffer  is one of those because it is a  regular -er verb. We take the stem of  chauff  and add particular endings according to the subject and tense. These same endings are used for similar verbs like  brà »ler  (to burn) and  allumer  (to light), making each a little easier to learn than the first. Using the chart, pair the subject pronoun to the proper tense for your subject. For example, I heat is je chauffe and we will heat is nous chaufferons. Subject Present Future Imperfect je chauffe chaufferai chauffais tu chauffes chaufferas chauffais il chauffe chauffera chauffait nous chauffons chaufferons chauffions vous chauffez chaufferez chauffiez ils chauffent chaufferont chauffaient The Present Participle of  Chauffer The  present participle  of chauffer  is chauffant. For this conjugation, it is as easy as adding -ant  to the verb stem. It is used as a verb and will also work as an adjective, gerund, or noun when needed. The Past Participle and Passà © Composà © A  common way to express the past tense heated in French is to use the  passà © composà ©. To do this, conjugate the  auxiliary, or helping verb  avoir  to the correct subject, then add the  past participle  chauffà ©. For instance, I heated becomes jai chauffà © and we heated is nous avons chauffà ©. You should note that  ai  and  avons  are conjugates of  avoir.  Also, the past participle does not change when the subject does. More Simple  Chauffer  Conjugations to Know At first, students should focus on the present, past, and future forms of  chauffer  as these are used most often. With experience, you may also find a use for the subjunctive or conditional verb forms. Both of these imply some degree of uncertainty to the verb. In rare instances and primarily in literature, you will see the passà © simple and imperfect subjunctive forms of  chauffer. While you may not use or need them yourself, you should at least be able to recognize and associate them with to heat. Subject Subjunctive Conditional Passà © Simple Imperfect Subjunctive je chauffe chaufferais chauffai chauffasse tu chauffes chaufferais chauffas chauffasses il chauffe chaufferait chauffa chauffà ¢t nous chauffions chaufferions chauffà ¢mes chauffassions vous chauffiez chaufferiez chauffà ¢tes chauffassiez ils chauffent chaufferaient chauffà ¨rent chauffassent For short and direct exclamations, use  chauffer  in the imperative form. To do so, theres no need to include the subject pronoun. Rather than saying tu chauffe, you can simply say chauffe. Imperative (tu) chauffe (nous) chauffons (vous) chauffez