Semiconservative DNA replication means that after one round of replication, each daughter DNA double helix contains which combination of strands?

• A. Two newly synthesized strands with no parental strands
• B. Two parental (old) strands conserved together and a separate duplex of two new strands is made
• C. Each strand is a patchwork containing alternating old and new DNA segments
• D. One parental (old) strand and one newly synthesized strand

Answer: (D)

Verified step by step guidance

1. Understand the concept of semiconservative DNA replication: during DNA replication, the double helix unwinds and each original (parental) strand serves as a template for the synthesis of a new complementary strand.
2. Recognize that after one round of replication, each daughter DNA molecule consists of one strand from the original parental DNA and one newly synthesized strand.
3. Contrast semiconservative replication with other models: conservative replication would produce one entirely old double helix and one entirely new double helix, while dispersive replication would produce strands that are mixtures of old and new DNA segments.
4. Apply this knowledge to the problem: since semiconservative replication preserves one parental strand in each daughter molecule, the correct combination after one round is one parental (old) strand paired with one newly synthesized strand.
5. Summarize that this mechanism ensures genetic continuity by conserving half of the original DNA molecule in each daughter DNA double helix.