In semiconservative DNA replication, what is true about the two replicated DNA molecules?

In semiconservative DNA replication, what is true about the two replicated DNA molecules?

• A. Both copies contain both original strands
• B. The original DNA is completely copied into two identical new molecules
• C. Each replicated DNA molecule contains one original strand
• D. DNA replication creates RNA templates

Answer: (C)

In semiconservative DNA replication, each of the two new DNA molecules ends up with one strand that came from the original parent molecule and one newly synthesized strand. The two strands of the original double helix separate, and each serves as a template for a complementary new strand. Because base pairing is precise (A pairs with T, G with C) and DNA polymerase builds in the 5′ to 3′ direction, the result is two daughter molecules, each containing one old strand and one new strand. This is why the statement that each replicated DNA molecule has one original strand is the best description. It reflects how the parental information is preserved in each new double helix rather than creating two completely new copies or splitting the original intact helix entirely. The other ideas—both copies retaining both original strands (conservative model), the original being copied wholesale into two new molecules, or replication creating RNA templates—do not describe how DNA replication actually works (RNA primers are used briefly, but the template is DNA, and one original strand remains in each daughter).

In semiconservative DNA replication, each of the two new DNA molecules ends up with one strand that came from the original parent molecule and one newly synthesized strand. The two strands of the original double helix separate, and each serves as a template for a complementary new strand. Because base pairing is precise (A pairs with T, G with C) and DNA polymerase builds in the 5′ to 3′ direction, the result is two daughter molecules, each containing one old strand and one new strand.

This is why the statement that each replicated DNA molecule has one original strand is the best description. It reflects how the parental information is preserved in each new double helix rather than creating two completely new copies or splitting the original intact helix entirely. The other ideas—both copies retaining both original strands (conservative model), the original being copied wholesale into two new molecules, or replication creating RNA templates—do not describe how DNA replication actually works (RNA primers are used briefly, but the template is DNA, and one original strand remains in each daughter).