Viruses are isolated from wild-type E. coli cells that have been infected with wild-type bacteriophage ?. These viruses are used to infect a Gal? strain of E. coli. A few bacterial colonies that can grow on galactose are obtained, while no bacteria that can grow on galactose are obtained from cells that were not infected. What has happened?
A) A ? gal+ phage was generated.
B) Reversion mutations have occurred.
C) The bacteria underwent conjugation with a Gal+ strain.
D) The bacteria underwent transformation with a wild-type E. coli strain.
A) A ? gal+ phage was generated.
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The term oxidation is derived from the name of the element oxygen. This is reasonable, because oxygen
A. attracts electrons very strongly. B. can be oxidized by accepting electrons. C. contains more electrons than are needed. D. passes electrons to many other types of molecules.
A typhoon devastates a population on "island A" and only a few individuals survive. Several generations later, the replenished population suffers from several inherited disorders that are very rare in other groups. A genetic event that explains this is
A) a population bottleneck. B) genetic load. C) a founder effect. D) natural selection.
Small doses of ionizing radiation over a long period of time cause less damage because
a. they are too low to affect cells. b. they don't hit as many targets. c. the body has time to repair damaged DNA. d. the radiation is absorbed by macrophages. e. the radiation is absorbed by red blood cells.
In a chemical synapse, what is the name of the gap between the transmitting and receiving neurons?
What will be an ideal response?