Question

In Seymour Benzer's studies, if he mixed two RII phage together (co-infection studies in K12) and the resulting

phage always failed to lyse K12 ________.
A) the two mutants were in different cistrons
B) the two mutants failed to infect bacteria
C) the two mutants were in the same cistron
D) the two mutants complemented each other
E) the two mutants represented mutations in both A and B

Answer 1

When Seymour Benzer mixed two RII phage mutants together and they failed to lyse K12, it indicated that the two mutants were in the same cistron, as they did not complement each other to restore the lytic function.

Step-by-step explanation:

In Seymour Benzer's studies, if he mixed two RII phage together (co-infection studies in K12) and the resulting phage always failed to lyse K12, then the two mutants were in the same cistron. This means that both mutants had defects within the same functional unit or gene necessary for the phage to lyse the K12 bacteria. If they had been in different cistrons, one would expect the two mutants to complement each other's defects, allowing the viruses to lyse the bacteria. This outcome indicates a failure of complementation, which happens when two mutations are in the same functional genetic segment and hence cannot provide the necessary function between them to make the virus viable.