4. Gram Staining Archaea
(Not for the same reasons as Bacteria.)
* Gram+ cell wall like with Gram+ Bacteria, but different
biochemical composition that peptidoglycan.
* Gram–
due to glycoprotein surface layer not an
outer membrane.
* Some with NO cell wall!
+ -
5. Pseudomurein
(Murein = NAG-NAM of
peptidoglycan in Bacteria)
* Insensitive to penicillin.
* NAM replaced by NAT
* Unique side-chain peptide
cross-links.
10. Methanogens
Obligate anaerobes dependent on fermentation bacteria.
Chemoheterotrophic:
Acetoclastic
Acetate to CO2 and methane
Chemoautotrophic:
H2 or formate as energy & electron source
CO2 to methane and other cellular
components
11.
12. Methanogenesis Pathway
MCR protein is a 3
component complex;
Component C is made of 3
polypeptide subunits (α,β,γ)
encoded on mcrA, mcrB,
and mcrG genes.
14. Aerobic respiration yields greatest energy due to very positive
O2 redox potential.
Without O2, anaerobic respiration uses alternate terminal
electron acceptors in the order of decreasing redox potential.
E = -240 mV
Methanogenesis
E = +820 mV
E = +420 mV
E = -200 mV