DNA replication is described as semiconservative. What does this mean?

• A. Each daughter DNA double helix contains two newly synthesized strands and no parental strands.
• B. Each daughter DNA double helix contains two parental (old) strands that reassociate after replication.
• C. The parental DNA is fragmented, and each daughter molecule contains a mixture of old and new DNA segments within each strand.
• D. Each daughter DNA double helix contains one parental (old) 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 copies its DNA before cell division, ensuring each daughter cell receives an identical set of genetic information.
2. Recall the three models of DNA replication proposed historically: conservative, semiconservative, and dispersive replication.
3. Define semiconservative replication: In this model, each of the two parental DNA strands serves as a template for a new strand, resulting in two DNA molecules, each composed of one old (parental) strand and one newly synthesized strand.
4. Contrast semiconservative replication with other models: Conservative replication would produce one molecule with both old strands and one with both new strands, while dispersive replication would produce strands with interspersed old and new DNA segments.
5. Conclude that the semiconservative model explains that each daughter DNA double helix contains one parental strand and one newly synthesized strand, preserving half of the original molecule in each new DNA.