Why is DNA replication described as semiconservative?

• A. The parental DNA is fragmented, and the fragments are randomly distributed between daughter molecules.
• B. Each daughter DNA molecule contains two newly synthesized strands and no original (parental) DNA.
• C. Each daughter DNA molecule contains two original (parental) strands and no newly synthesized DNA.
• D. Each daughter DNA molecule contains one original (parental) 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 structure of DNA: DNA is composed of two complementary strands forming a double helix, with each strand serving as a template during replication.
3. Define semiconservative replication: In semiconservative replication, each of the two daughter DNA molecules contains one original (parental) strand and one newly synthesized strand.
4. Contrast semiconservative replication with other models: The conservative model suggests one daughter molecule has both original strands and the other has both new strands, while the dispersive model suggests parental DNA is fragmented and mixed randomly in daughter strands.
5. Recognize that experimental evidence (e.g., Meselson-Stahl experiment) supports the semiconservative model, confirming that each daughter DNA molecule retains one parental strand paired with one new strand.