E. coli cells grown on ¹⁵N medium are transferred to ¹⁴N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment?
A) one high-density and one low-density band
B) one intermediate-density band
C) one high-density and one intermediate-density band
D) one low-density and one intermediate-density band
E) one low-density band

Question

Quizplus · Accepted Answer

After two rounds of DNA replication following the transfer from ¹⁵N to ¹⁴N medium, there will be a mix of DNA molecules: some with one strand of ¹⁵N and one of ¹⁴N (intermediate-density) and others with both strands of ¹⁴N (low-density).

E Coli Cells Grown on ¹⁵N Medium Are Transferred to ¹⁴N