In the semiconservative model, what is the composition of each newly formed DNA molecule?

In the semiconservative model, what is the composition of each newly formed DNA molecule?

• A. Both strands are newly synthesized
• B. Both strands are old parental strands
• C. One old parental strand and one new daughter strand
• D. One RNA strand and one DNA strand

Answer: (C)

Semiconservative replication means each newly formed DNA molecule contains one old parental strand and one newly synthesized strand. When the double helix unwinds, each parental strand acts as a template, and DNA polymerase builds a complementary new strand in the 5' to 3' direction. The result is two DNA molecules, each with one original strand and one new strand. RNA primers are temporary during synthesis and are removed, so the final product is two DNA duplexes; having both strands newly synthesized or both strands old would contradict this model.

Semiconservative replication means each newly formed DNA molecule contains one old parental strand and one newly synthesized strand. When the double helix unwinds, each parental strand acts as a template, and DNA polymerase builds a complementary new strand in the 5' to 3' direction. The result is two DNA molecules, each with one original strand and one new strand. RNA primers are temporary during synthesis and are removed, so the final product is two DNA duplexes; having both strands newly synthesized or both strands old would contradict this model.