Archea

Question 1

What were the original 2 categories of Archea?

Answer 1

Euyarchea and Crenarchea

Question 2

How was the TACK superphylum realised and what is it composed of?

Answer 2

Recent genome sequencing

• Thaumarchaeota
• Aigarchaeota
• Crenarchaeota
• Korarchaeota

Question 3

How is the eucarya group proposed to have originated?

Answer 3

Endosymbiotic event: Probacterium captured to become a mitochondrion

Question 4

Describe the structure of archeal membranes

Answer 4

Are formed from isoprene chains with L-glycerol and ester linkages which form an extremely stable structure, enabling archea to inhabit extreme environments

Question 5

Describe the metabolism of methanogens

Answer 5

Methanogenesis: CO2 + H2 –> CH4

Question 6

Describe halophile archea

Answer 6

Live in saturated salt (5.5M concentrations) and have high intracellular salt concentrations
Membrane contains a light driven pump which pumps H+ out of the cell, and 7 membrane spanning helices which form ATP from the chemiosmotic gradient. A retinal co factor gives a red colour.

Question 7

How do marine archea (thaumarchea) metabolise?

Answer 7

Fix inorganic carbon and convert ammonia to nitrite, hence important for global nitrogen cycles

Question 8

What are the upper and lower temperature limits for archeal life?

Answer 8

120 degrees C and 0 degrees C