The process of DNA synthesis in which the two original strands separate and each acts as a template for a new strand is known as what?

• A. Conservative replication
• B. Semi-Conservative replication
• C. Dispersive replication
• D. Replicative Synthesis

Answer: (B)

Semi-conservative replication is how DNA is copied: the two parental strands unwind and separate, and each serves as a template for a new complementary strand. Because each new strand pairs with its old partner, every daughter DNA molecule ends up with one original strand and one newly synthesized strand. This pattern was confirmed by experiments showing that old and new strands segregate into separate molecules after replication, notably in the Meselson–Stahl study.

Other theoretical patterns don’t fit what’s observed: conservative replication would yield one molecule with both original strands and another with both new strands, which isn’t what happens; dispersive replication would produce mixtures of old and new DNA within each strand, not the clean old/new duplexes seen; the term replicative synthesis isn’t a standard way to describe the mechanism of copying DNA.