DNA is described as replicating in a semi-conservative manner. Meselson and Stahl’s experimental results provided very strong evidence for this theory. They worked with E. coli, which has a generation time of 50 minutes. The steps in their experiment are listed below, but they are not in the right order. P: Every bacterium contains $^{15}\text{N}$ DNA. Q: Every bacterium contains hybrid DNA ($^{15}\text{N}$ DNA and $^{14}\text{N}$ DNA). R: Bacteria contain either only $^{14}\text{N}$ DNA or hybrid DNA. S: Bacteria were grown in a $^{15}\text{N}$ medium for many generations. T: Bacteria were moved to a $^{14}\text{N}$ medium and taken as samples every 50 minutes. Which sequence of letters gives the correct order of the experimental steps?
- AP → Q → R → S → T
- BP → S → T → R → Q
- CS → P → T → Q → R
- DS → R → Q → P → T