Many bacteria, including E. coli, are capable of growing under both anaerobic and aerobic conditions. some mutations are introduced into an E. coli strain that inactivate several enzymes involved in DNA repair. The mutant strain grows normally when kept in a incubator with a 100% nitrogen gas atmosphere. however, the strain dies when exposed to a normal labroratory atmosphere. why?
a. nitrogen stabilizes the enzyme responsible for DNA repair, while oxygen destabilized these enzymes
b. reactive oxygen species generated during normal aerobic metabolism from free radicals are a major source of DNA damage
c. deamination of cytosine, which introduces mismateched nucleotides, occurs at a higher frequency in aerobic conditions compared to anaerobic conditions.
Many bacteria, including E. coli, are capable of growing under both anaerobic and aerobic conditions. some mutations are introduced into an E. coli strain that inactivate several enzymes involved in DNA repair. The mutant strain grows normally when kept in a incubator with a 100% nitrogen gas atmosphere. however, the strain dies when exposed to a normal labroratory atmosphere. why?
a. nitrogen stabilizes the enzyme responsible for DNA repair, while oxygen destabilized these enzymes
b. reactive oxygen species generated during normal aerobic metabolism from free radicals are a major source of DNA damage
c. deamination of cytosine, which introduces mismateched nucleotides, occurs at a higher frequency in aerobic conditions compared to anaerobic conditions.
