Question

Bacteriophage viruses were produced in the presence of radioactively tagged materials, resulting in the presence of both radioactive proteins and radioactive nucleic acids in the viruses.
These viruses were then allowed to infect bacteria in normal growth medium. Viruses produced during the lytic cycle were sampled for radioactivity.
What parts of the virus should show radioactivity?

• A. Neither the proteins nor the nucleic acids
• B. Only the proteins
• C. Only the nucleic acids
• D. Both the protein and the nucleic acids

Answer 1

Answer: (A)

Neither the proteins nor the nucleic acids

In the life cycle of viruses there are two cycles; first is the lytic cycle which is the lysis of the host cell with all its contents and the lysogenic cycle which is to the production of viral DNA into the host.

During the lytic cycle, the viral DNA exists as a separate molecule and it also replicates separately from the host DNA, so there is no interference of the host DNA with the viral DNA.

Therefore during this time, the virus will not show any type of radioactivity in either of its protein or nucleic acid.

So, the correct option is 'Neither the proteins nor the nucleic acids'