Clokie 1 Archea Flashcards
Where do Archea live?
Hot springs, 100’C,
acidic / alkaline extremes
Hypersaline = salt ponds
Some with no oxygen= hostile environment
Contribute to how much biomass
<20%
• Major part of global ecosystms
Differences between Archaea & Bacteria cell walls
- Archaea: NO PEPTIDOGLYCAN, pseudomurein, sugars,
* proteins or glycoproteins
Differences in Arachea
1 Lipids
Archaea
1 branched isoprene chains
2 L-glycerol
3ether-linked lipids
Bacteria & Eukaryotes
1 unbranched fatty acids
2D-glycerol
6 ester-linked lipids
Similarities in Archaea lipids
have phosphate
Differences in Archaea
2 Flagella
- Bacterial: helical filaments
- thicker and hollow
- archaeal flagella grow by the addition to the base
Differences in Archaea
3 Polymerase
RNA Polymerase => 5 proteins, more similar in A & E than B
Methanogens
make. ..
live. .
makes methane using 3 pathways
- Diverse physiology
- diverse habitats
- Anerobi environments
- large genomes
Methanogenesis
• CO2 + 4 H2 →
break down of organic matter.
→ CH4 + 2H2O
Methanogenesis Terminal electron acceptor is
carbon electron acceptors (such as O2, S, NO3) are depleted while H2 and CO2 increase
Without methanogenesis ..
….lots of carbon (fermentation products) accumulate in anaerobic environments
Fastidious anaerobes
can’t cope with O2 (hydrogenotrophic, acetotrophic, methlyotrophic pathways to make methane)
Methanogenesis organisms x3
Methanosarcina, Methanobacterium, Methanococcus
nitrogen cycle
ammonia oxidation
• Increases availability of N for uptake by plants
Nitrification
Links fixed and mineralised forms of organic nitrogen to denitrification
• NO3- leached from soil results in groundwater pollution
• NO3- available for denitrification processes
• Generates N2O (greenhouse gas & depletes ozone)
