The organism Methanopyrus kandleri is an obligate anaerobe but performs respiration using H2
and CO2 as the endpoints of the electron transport chain. Looking at the slide you have from
lecture, which of these statements best explains its metabolism?
a. H+ is used as an electron donor, while methane (CH4) is used as the electron acceptor. Most
of the CO2 consumed is used for fixation into organic carbon for both structural and non-
structural purposes.
b. It is a carbon fixer, using CO2 from the atmosphere to build organic compounds. Only a small
part of the CO2 captured is put into organic compounds, the rest is put into inorganic molecules.
It uses H2 instead of H2O for its photosynthetic reactions.
c. Methane (CH4) represents most of the carbon source of this methanogen. The electrons for
energy production come from H2 and CO2 is used to capture those electrons and then turned into
CH4, where most of the carbon comes from for this species. Only a small fraction of the organic
carbon it obtains comes from fixing CO2 directly.
d. H2 is used as an electron donor and CO2 is used as an electron acceptor producing methane,
while CO2 is fixed, independently, into organic carbon for growth and metabolism. The majority
of the CO2 consumed does not end up as structural carbon.
e. None of the answers provided here are satisfactory..
The organism Methanopyrus kandleri is an obligate anaerobe but perfo.pdf
1. The organism Methanopyrus kandleri is an obligate anaerobe but performs respiration using H2
and CO2 as the endpoints of the electron transport chain. Looking at the slide you have from
lecture, which of these statements best explains its metabolism?
a. H+ is used as an electron donor, while methane (CH4) is used as the electron acceptor. Most
of the CO2 consumed is used for fixation into organic carbon for both structural and non-
structural purposes.
b. It is a carbon fixer, using CO2 from the atmosphere to build organic compounds. Only a small
part of the CO2 captured is put into organic compounds, the rest is put into inorganic molecules.
It uses H2 instead of H2O for its photosynthetic reactions.
c. Methane (CH4) represents most of the carbon source of this methanogen. The electrons for
energy production come from H2 and CO2 is used to capture those electrons and then turned into
CH4, where most of the carbon comes from for this species. Only a small fraction of the organic
carbon it obtains comes from fixing CO2 directly.
d. H2 is used as an electron donor and CO2 is used as an electron acceptor producing methane,
while CO2 is fixed, independently, into organic carbon for growth and metabolism. The majority
of the CO2 consumed does not end up as structural carbon.
e. None of the answers provided here are satisfactory.
