Which model best describes the mechanism of DNA replication in cells?

• A. Translational model
• B. Dispersive model
• C. Semiconservative model
• D. Conservative model

Answer: (C)

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. This ensures that each daughter cell receives an identical copy of the genetic material.
2. Learn about the semiconservative model: The semiconservative model of DNA replication suggests that each of the two strands of the original DNA molecule serves as a template for the synthesis of a new complementary strand. After replication, each DNA molecule consists of one original strand and one newly synthesized strand.
3. Compare the semiconservative model with other models: The conservative model suggests that the original DNA molecule remains intact and a completely new molecule is synthesized. The dispersive model proposes that the original DNA is fragmented and both old and new DNA are interspersed in the replicated molecules.
4. Understand why the semiconservative model is correct: Experiments, such as the Meselson-Stahl experiment, demonstrated that DNA replication follows the semiconservative model. This experiment used isotopes of nitrogen to track the distribution of DNA strands during replication, confirming that each new DNA molecule contains one original strand and one new strand.
5. Conclude that the semiconservative model best describes DNA replication: Based on experimental evidence and the mechanism of template-directed synthesis, the semiconservative model is the correct and widely accepted explanation for DNA replication in cells.