L24:

Question 1

Methanogens

Answer 1

extreme anaeorbes
*only in archaea across many phylas
*via complex metabolism, based on e- transfer reactions on membrane bound enzymes and co enzymes which allow CO2 as electron acceptor (dumps e- to CO2)
*key in C cycle, many combination of e-acceptors and donors

Question 2

List all the unique co enzymes for methonogens

Answer 2

MM C FF
MP, MF, CoM, F430 F420

Question 3

methanogenesis equation, break it down

Answer 3

H2 (energy source) + CO2 (C source) = CH4

*H2 is oxidised as energy source and e- donor
*CO2 is e- acceptor and C source=autotroph
*CH4 is waste product

Question 4

methongesis e- accors and donors other options

Answer 4

fermentation waste products

different e-donors and acceptors can be used: acetate, formate, methanol, methylmine and diemythlsuflphate

Question 5

List methanogenic habitats

Answer 5

widespread, aneorbic zomes below fermenation layers, swamps, sediments, garbage, ruminants, stomach

Question 6

How will the cycle for methanogensis look like

Answer 6

side chains dumping e- (Falling down) to be productive, a version of ETC and methane is the result product

Question 7

Net emission formula

Answer 7

production - oxidation
6*10^14

Question 8

top methan emmisions

Answer 8

natural wetlands
rice fields
ruminants
ocean/freshwater
gas leakage

Question 9

Relationship between fermentation and methanogensis

Answer 9

in aneorbix zones, fermentation products feed methanogensis

*fermentation product like cellulose, polysaccharides and proteins are substrates that feed methanogens

*hydrolisis, fermentation to H2 + CO2, acetate or other organic compounds

*intermediate products acetogensis and secondary fermentation of organic acids/alcohols yield the substractes

Question 10

draw methane production from fermentation

Answer 10

check slide 141

Question 11

what is the role of ANME archea in methanogensis, draw this

Answer 11

They drive methane accumulation/removal in estuarine sediments

*fermenters produce hydrogen from organic matter
*in anaerobic oxidation of methane, sulfate reducers bring H concentration so low that methane oxidation is exergenonic
*then during methanogenesis, the SRB have run out of sulphate so hydrogen concentration building up that make ANME switch to forward methanogensis

Question 12

What were the two approaches to molecular microbial ecology

Answer 12

1. quantitative hybridisation
2. phylogenetic characterisation

Question 13

In depth go into quantitative hybridisation

Answer 13

To determine the relative proportions of organisms from different phylogenetic groups in a sample

– quantify the RNA or DNA extracted from the environmental samples blotted onto membranes

– today we might opt for quantitative PCR, microarray or metagenomic sequencing, but the goal is the same

Question 14

Explain Phylogenetic characterization

Answer 14

To identify organisms via molecular analysis of nucleic acids extracted from a sample
– PCR-amplification of 16S rRNA genes, followed by cloning of the amplified DNA and analysis of the DNA sequences

Question 15

What level of methodological detail

Answer 15

1. reproducible
2. allow research to extrapolate new methods
3. helps others learn new techniques