Nitrogen is an important element in DNA and proteins; however,atmospheric nitrogen is the only source of this
element for life on Earth and itcannot be absorbed by eukaryotes. As a result, nitrogen? fixingbacteria species,
such as Rhizobia,live in a mutualistic relationship with plants like legumes. Thesespecies of bacteria are
obligate aerobes.
a. Explain what is meant by the term "obligate aerobe" and howthat relates to Rhizobia metabolism.
b. What is the role of each organism in theRhizobia?legume mutualistic relationship?
c. There is a theory that legumes are deliberately drivingRhizobia evolution by cutting off nutrient supplies
for those bacteria that fix less nitrogen. What would you expect tosee in a Rhizobiapopulation if this
theory is true and why?
Nitrogen is an important element in DNA and proteins; however,atmospheric nitrogen is the only source of this
element for life on Earth and itcannot be absorbed by eukaryotes. As a result, nitrogen? fixingbacteria species,
such as Rhizobia,live in a mutualistic relationship with plants like legumes. Thesespecies of bacteria are
obligate aerobes.
a. Explain what is meant by the term "obligate aerobe" and howthat relates to Rhizobia metabolism.
b. What is the role of each organism in theRhizobia?legume mutualistic relationship?
c. There is a theory that legumes are deliberately drivingRhizobia evolution by cutting off nutrient supplies
for those bacteria that fix less nitrogen. What would you expect tosee in a Rhizobiapopulation if this
theory is true and why?
