Figure 13.1
-A space probe returns with a culture of a microorganism found on a distant planet. Analysis shows that it is a carbon-based life-form that has DNA. You grow the cells in 15N medium for several generations and then transfer them to 14N medium. Which pattern in Figure 13.1 would you expect after one round of DNA replication if the DNA was replicated in a conservative manner?
A) A
B) B
C) C
D) D
E) E

Question

Figure 13.1
-A space probe returns with a culture of a microorganism found on a distant planet. Analysis shows that it is a carbon-based life-form that has DNA. You grow the cells in 15N medium for several generations and then transfer them to 14N medium. Which pattern in Figure 13.1 would you expect after one round of DNA replication if the DNA was replicated in a conservative manner?
A) A 
B) B 
C) C 
D) D 
E) E

Quizplus · Accepted Answer

If DNA replication occurred in a conservative manner, the original DNA strands (labeled with 15N) would remain together and the newly synthesized strands (labeled with 14N) would be together. This would result in one band of DNA with both strands labeled with 15N and another band with both strands labeled with 14N, as shown in pattern B.

Figure 13.1 -A Space Probe Returns with a Culture of a Microorganism