What does semi-conservative replication mean?

What does semi-conservative replication mean?

• A. Each daughter molecule contains one old strand and one new strand
• B. Both strands are newly synthesized
• C. DNA is replicated using RNA templates
• D. The two strands separate and both become old

Answer: (A)

In semi-conservative replication, each new DNA molecule ends up containing one strand that was part of the original double helix and one newly synthesized strand. The two strands separate, each old strand serving as a template for building a matching new strand, so every daughter molecule has one old and one new strand. This is the pattern supported by experiments like Meselson–Stahl and is the standard mechanism of DNA replication. The other ideas describe different possibilities: both strands newly synthesized would be a fully new-copy model, using RNA templates would be a different replication scenario, and the notion that both strands become old doesn’t reflect the creation of new genetic material during replication.

In semi-conservative replication, each new DNA molecule ends up containing one strand that was part of the original double helix and one newly synthesized strand. The two strands separate, each old strand serving as a template for building a matching new strand, so every daughter molecule has one old and one new strand. This is the pattern supported by experiments like Meselson–Stahl and is the standard mechanism of DNA replication.

The other ideas describe different possibilities: both strands newly synthesized would be a fully new-copy model, using RNA templates would be a different replication scenario, and the notion that both strands become old doesn’t reflect the creation of new genetic material during replication.