Why is DNA replication described as semiconservative?

• A. Each daughter DNA molecule is composed entirely of newly synthesized DNA strands.
• B. Only the leading strand is newly synthesized, while the lagging strand is inherited unchanged.
• C. Each daughter DNA molecule contains one original (parental) strand and one newly synthesized strand.
• D. Both parental strands remain paired together and are copied without separating.

Answer: (C)

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 double-stranded, with two complementary strands running in opposite directions, held together by base pairing.
3. Define semiconservative replication: In semiconservative replication, each of the two original DNA strands serves as a template for a new strand, resulting in two DNA molecules each composed of one original (parental) strand and one newly synthesized strand.
4. Contrast semiconservative replication with other models: Conservative replication would produce one molecule with both original strands and one with both new strands, while dispersive replication would produce strands with interspersed old and new segments.
5. Conclude why DNA replication is semiconservative: Because experimental evidence shows that after replication, each daughter DNA molecule retains one parental strand paired with one newly synthesized strand, the process is described as semiconservative.