How is genetic information preserved during the copying of DNA?

• A. Through the semi-conservative mechanism of DNA replication
• B. Through the dispersive mechanism of DNA replication
• C. By the random mechanism of DNA replication
• D. By the conservative mechanism of DNA replication

Answer: (A)

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, ensuring that each new cell receives a complete set of genetic information.
2. Learn about the semi-conservative mechanism: In semi-conservative replication, each of the two strands of the original DNA molecule serves as a template for the production of a complementary strand. This results in two DNA molecules, each with one old strand and one new strand.
3. Compare with other mechanisms: The conservative mechanism would involve creating a completely new DNA molecule while keeping the original intact, which does not happen in nature. The dispersive mechanism would involve mixing old and new DNA segments within the same strand, which is not supported by experimental evidence.
4. Explore the experimental evidence: The semi-conservative model was confirmed by the Meselson-Stahl experiment, which used isotopic labeling to demonstrate that DNA replication results in molecules with one old and one new strand.
5. Conclude with the preservation of genetic information: The semi-conservative mechanism ensures that genetic information is accurately preserved and passed on to daughter cells, maintaining the integrity of the genetic code.