An Hfr strain has a plasmid inserted near the trp (tryptophan)locus.This Hfr strain is incubated with an F- trp- strain.We isolate a trp+ strain that can readily donate this trait to other trp- strains.No other traits are transferred.What has happened?
A) an F+ trp plasmid has been generated B) typical Hfr mating C) transduction occurs D) transformation occurs E) no change in genotype has occurred
Two bacteria grow together.One appears to donate DNA to the other.One of the bacteria contains a bacteriophage that is normally quiescent but occasionally forms a plaque.What sort of genetic exchange is most likely to be occurring?
A) transformation B) conjugation C) transduction D) electroporation E) transposition
Certain protozoa engulf cyanobacteria (photosynthetic bacteria)and maintain a given number of the cyanobacteria even when they divide.The protozoa divide only after the cyanobacteria have doubled their number.The cyanobacteria excrete glucose that the protozoa use for energy.This is a good example of
A) parasitism by protozoa. B) how protozoa consume particulate food. C) establishment of an endosymbiotic relationship. D) symbiosis between two microorganisms. E) convergent evolution.