Archaea

How are archaea the most ecologically diverse

They are the oldest known lineage and can live in extreme environments. They are classified as psychrophiles=extreme cold, hyperthermophiles=extreme hot, Methanogens=only known group to produce methane gas, acidophiles=acidic, and halophiles= high salt. They can also be seen in moderate habitats such as the open ocean, soil and surface of plant roots. None of the archaea are pathogenic

What are some traits of archaea

The archael signatures are cell membrane lipids, cell wall components, certain metabolic pathways, certain genome features

How are the archael lipids different from bacterial lipids?

archael lipids use L glycerol and not D glycerol, they have ether linkages between the glycerol to withstand extreme environments, they have branched chains of lipids made from isoprenoid units and NO unsaturation fatty acids (lipids)

They can also be more exotic in form by being macrocylclic diether (helps maintain fluidity in membrane), Tetraether (makes a single layer both chains linked together) and cyclopentane rings (more for extremophiles)

Give some characteristics of the archael cell wall

The cell wall lacks peptidoglycan and has a S layer (proteins and carbohydrates). The methanogens have a pseudopeptidoglycan. Their carbohydrates are N-acetyltalosaminuronic acid. They have B(1,3) linkages instead of B (1,4) linkages. They are resistant to lysozymes which provide protection. Archaea also have different types of cross bridges which are resistant to peniillin.

Some archaea possess no cell wall at all and only an S layer composed of protein

How is glucose catabolized in archae

Glucose is catabolized by different variants of Entner-Doudoff Pathway (ED) and Embden-Meyerhoff-Parnas Pathway (EMP)

We rarely have the PPP pathway in true bacteria

What is methanogenesis

the ability to produce methane gas which is unique to archaea

CO2 is reduced to methane gas

Explain methanogenesis

Take biomolecule and goes through hydrolysis (phase 1) which is broken down into monomers (catabolism), Then can enter acidogenesis (phase 2) where it fermentate (propionic acid or burtyonic acid). Then enters acetogenesis (phase 3) where it can choose to make acetate or H2 and CO2. Finally in methanogenesis (phase 4) there are two type CO2 reducing methanogens reduce CO2 into methane gas or acetoclastic methanogens which reduce acetate into CO2 and methane gas

Where can methanogens be found

They can be found in ruminants digestive tract, soil, water, deep sea floor

How does methane affect climate change

It affects the greenhouse gases that protect us from the ozone layer. It is naturally occurring from the methanogens or anthropogenic meaning burning biogas or burning fossil fuels

What are some unique features of archael genomes

They have a reverse gyrase of hyperthermophiles that help maintain high temperatures in the environment because they are able to supercoil the DNA and maintain it

How is the genome of archaea similar to bacteria

It has circular genome, It gene size and density are similar, it also has operons present

How is the archael genome similar to eukaryotes

It has a presence of introns, The RNA polymerase has similar transcription factor (TBP and TFIIB which are looking for promoters which is the TATA binding protein), Lastly the presence of histone homologs which is a protein that help DNA maintain organization of DNA molecule