Why is DNA replication described as semiconservative?

• A. The two parental strands separate, and each daughter DNA molecule contains two newly synthesized strands while the parental strands are degraded.
• B. Each daughter DNA molecule contains one parental (template) strand and one newly synthesized strand.
• C. Both strands of the parental DNA molecule remain together, and an entirely new double-stranded DNA molecule is synthesized separately.
• D. Parental DNA is broken into fragments, and each fragment serves as a template to produce a mosaic daughter molecule containing interspersed old and new DNA segments within each strand.

Answer: (B)

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 parental DNA strands serves as a template for the synthesis of a new complementary strand.
4. Explain the outcome of semiconservative replication: After replication, each daughter DNA molecule consists of one original (parental) strand and one newly synthesized strand, preserving half of the original molecule in each daughter DNA.
5. Contrast with other models: This differs from conservative replication (where parental strands stay together) and dispersive replication (where parental DNA is fragmented and mixed), highlighting why semiconservative replication is the correct description.