Humans Have Harmless E

question 38

Multiple Choice

Humans have harmless E. coli strains that reside in the intestines. O157:H7 is an E. coli strain reported to cause several food poisoning deaths. Evidence suggests that the virulence of O157:H7 is caused by genes from a virus that infects bacteria. Considering this evidence, which of the following statements most likely explains how the O157:H7 population acquired the genetic variation that distinguishes it from the harmless E. coli strains?

• A) The virus entered the bacterial cell, allowing the bacteria's cellular machinery to create new viruses.
• B) Viral envelope proteins bound receptors on the bacteria, allowing the viral genetic material to enter the cytoplasm and be translated into proteins that increased that bacterium's virulence.
• C) The virus entered the cell and reassorted to acquire specific genes from the bacteria to increase the virulence of the virus.
• D) The virus infected the bacterium, and the bacterial population replicated with a copy of the phage genome in each new bacterium.