Archaea: An Overview

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ArchaeaAn Overview

• Hugh B. Fackrell

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Three Domains

• Fossil Record Morphology
• Five Kingdoms- plants, animals, protistia, fungi
  , prokaryotes
• Prokaryotes - Eubacteria, Archeobacteria
• Cellular
• Three kingdoms,
• Eubacteria, Archaebacteria, Eukaryotes

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Domain

• Level of organization above the kingdom level
• Archaea (formerly Archaebacteria)
• Bacteria ( formerly Eubacteria)
• Eucarya (plants, animals, protista, fungi)

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Phylogeny
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Archaea Cell Membranes

• lack fatty acids
• contain ethers
• gylcerol diethers , bilayers
• Tetraethers form monolayers
• Fixed number of carbons in hydrocarbons
• flexibility via pentacylic rings
• Large amounts of nonpolar lipids
• isoprenoids eg squalene

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Archaea Cell Walls

• NO muramic acid
• NO D amino acids
• pseudopeptidoglycan (Methanobacterium)
• N acetyltalosaminuronic acid
• glycoprotein (Halobacterium)
• highly negative charge balances positive charges
  of sodium
• Protein

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Archaea Genetics

• Half size of bacterial genomes
• 1900 KB vs 4700 KB (E coli)
• Bacterial Similarities
• Polygenic mRNA
• Shine-Dalgarno sequences for ribosome binding
• Eucarya Similarities
• RNA polymerase II