Which of the following functional groups would you expect to find in aerobic iron- and sulfur-rich acidic mine drainage?
A) dissimilative iron-oxidizers
B) dissimilative iron-reducers
C) purple sulfur bacteria
D) purple sulfur bacteria and dissimilative iron-reducers
Nitrogenase is a critical enzyme in the nitrogen cycle because it catalyzes the
A) assimilation of ammonia.
B) dissimilative reduction of nitrate to nitrogen gas.
C) fixation of nitrogen gas into ammonia.
D) oxidation of nitrogen gas into nitrate.
Thioploca species contain large vacuoles that store ________, which is used to ________ under anaerobic conditions.
A) nitrate / oxidize sulfide
B) oxygen / oxidize sulfur
C) sulfur / reduce nitrate
D) glycogen / provide energy
The Bacteria and Archaea are the ONLY domains in which organisms exist that can
A) catalyze the transformation of inorganic nitrogen species for biosynthesis.
B) assimilate nitrite.
C) conserve energy from the transformation of inorganic nitrogen species.
D) catalyze the incorporation of inorganic nitrogen species into biomolecules.
Diazotrophs maximize nitrogenase activity by
A) closely coupling N2 fixation with high rates of photosynthesis.
B) fixing N2 at times when oxygen is absent or in low concentrations.
C) producing specialized structures to protect nitrogenase from oxygen.
D) producing specialized structures or fixing N2 at times when oxygen is absent to protect nitrogenase from oxygen.
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