Why is DNA replication described as semiconservative?

• A. Each daughter DNA molecule contains one parental (old) strand and one newly synthesized strand.
• B. Each daughter DNA molecule is made entirely of newly synthesized strands with no parental DNA retained.
• C. Each daughter DNA molecule contains both parental strands, while the new strands are discarded after replication.
• D. The parental DNA strands break into fragments and randomly rejoin with new fragments to form daughter molecules.

Answer: (A)

Verified step by step guidance

1. Understand the structure of DNA: DNA is composed of two complementary strands forming a double helix, where each strand serves as a template during replication.
2. Recall the process of DNA replication: The double helix unwinds, and each original (parental) strand acts as a template for synthesizing a new complementary strand.
3. Define semiconservative replication: In this model, each daughter DNA molecule consists of one original parental strand and one newly synthesized strand.
4. Compare with other models: Conservative replication would produce one molecule with both original strands and one with both new strands, while dispersive replication would mix old and new DNA segments randomly.
5. Conclude why semiconservative is correct: Because after replication, each daughter DNA molecule retains one parental strand paired with one new strand, preserving half of the original DNA in each molecule.