Which model and explanation best represents the semiconservative nature of DNA replication?

• A. Both strands of the parental DNA remain together, and an entirely new double helix is synthesized.
• B. Each daughter DNA molecule contains two newly synthesized strands.
• C. The parental DNA is randomly dispersed into two new double helices.
• D. Each daughter DNA molecule consists of one parental strand and one newly synthesized strand.

Answer: (D)

Verified step by step guidance

1. Understand the concept of DNA replication: DNA replication is the process by which a cell duplicates its DNA before cell division. The semiconservative model of DNA replication means that each new DNA molecule consists of one original (parental) strand and one newly synthesized strand.
2. Review the structure of DNA: DNA is a double helix composed of two complementary strands. During replication, the two strands separate, and each serves as a template for the synthesis of a new complementary strand.
3. Examine the semiconservative model: In this model, the parental DNA strands separate, and each strand is used as a template to synthesize a new strand. This results in two daughter DNA molecules, each containing one parental strand and one newly synthesized strand.
4. Compare the semiconservative model to other models: The conservative model suggests that the parental DNA remains intact and a completely new double helix is synthesized. The dispersive model suggests that the parental DNA is randomly fragmented and dispersed into the new DNA molecules. Neither of these models matches the semiconservative nature of DNA replication.
5. Conclude with the correct explanation: The semiconservative model is supported by experimental evidence, such as the Meselson-Stahl experiment, which demonstrated that each daughter DNA molecule consists of one parental strand and one newly synthesized strand.