During DNA replication, each daughter DNA molecule contains one old strand and one new strand. What is this type of replication called?

During DNA replication, each daughter DNA molecule contains one old strand and one new strand. What is this type of replication called?

• A. Conservative replication
• B. Semi-conservative replication
• C. Dispersive replication
• D. Replication fork model

Answer: (B)

The concept being tested is how genetic material is copied so that each new molecule retains half of the original material. In semi-conservative replication, the two strands of the original DNA separate, and each serves as a template for a new complementary strand. This produces two daughter DNA molecules, each containing one old strand and one newly synthesized strand. That one-old, one-new configuration after replication is the defining hallmark of semi-conservative replication, and it matches what is observed in cells. The other proposed models would lead to different patterns—conservative would yield one molecule with both old strands and another with both new strands, while dispersive would mix old and new segments within each strand—neither of which explains the observed daughter molecules.

The concept being tested is how genetic material is copied so that each new molecule retains half of the original material. In semi-conservative replication, the two strands of the original DNA separate, and each serves as a template for a new complementary strand. This produces two daughter DNA molecules, each containing one old strand and one newly synthesized strand. That one-old, one-new configuration after replication is the defining hallmark of semi-conservative replication, and it matches what is observed in cells. The other proposed models would lead to different patterns—conservative would yield one molecule with both old strands and another with both new strands, while dispersive would mix old and new segments within each strand—neither of which explains the observed daughter molecules.