Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?
A) One of the daughter cells, but not the other, would have radioactive DNA.
B) Neither of the two daughter cells would be radioactive.
C) All four bases of the DNA would be radioactive.
D) DNA in both daughter cells would be radioactive.

Question

Quizplus · Accepted Answer

When radioactive thymine is added to the radioactive culture of E. coli, it will be incorporated into the replicating DNA during the S phase of the cell cycle. Thus, both daughter cells will have a copy of the radioactive DNA, making option D the correct answer.

Suppose You Are Provided with an Actively Dividing Culture of E