[Campbell Biology P.370] Based on Figure 16.11, which statement accurately describes the DNA... | Practice Question

Based on Figure 16.11, which statement accurately describes the DNA molecules after two rounds of replication according to the semiconservative model?

  • A: All four DNA molecules would be composed entirely of new DNA.
  • B: Two DNA molecules would be entirely parental, and two entirely new.
  • C: Each of the four DNA molecules would consist of one old strand and one newly synthesized strand.
  • D: Two DNA molecules would contain one original strand and one new strand, while the other two would consist of two new strands.
  • E: All four DNA molecules would contain a mixture of old and newly synthesized DNA on both strands.

Explanation

In the semiconservative model Figure 16.11b , after the first round of replication, each of the two resulting DNA molecules consists of one old dark blue strand and one newly synthesized light blue strand. For the second round of replication, these two hybrid molecules each serve as templates. This leads to two new hybrid molecules one old, one new and two completely new molecules two new strands , making a total of two hybrid and two new molecules.