What is semi-conservative replication?

What is semi-conservative replication?

• A. Each Daughter DNA Molecule Contains One Parental Strand And One Newly Synthesized Strand
• B. Both Daughter DNA Molecules Contain Two Newly Synthesized Strands
• C. DNA Replicates By Transcribing To RNA First
• D. Replication Occurs Only In One Strand

Answer: (A)

Semi-conservative replication means that when a DNA molecule is copied, each of the two new DNA molecules contains one original (parental) strand and one newly synthesized strand. The parental strands serve as templates for building the complementary new strands, so every daughter molecule ends up with a mix of old and new material. This result was shown by experiments that tracked old versus new DNA strands. Think about what this implies for the other ideas: producing two entirely new strands would be a fully conservative model, which isn’t how DNA actually duplicates. Copying DNA is not the same as transcribing DNA into RNA, which is a separate process that makes RNA, not DNA. And replication doesn’t occur on just one strand; both strands are copied, though the synthesis on the two strands happens in different modes (continuous on one, discontinuous on the other) to form complete new double helices.

Semi-conservative replication means that when a DNA molecule is copied, each of the two new DNA molecules contains one original (parental) strand and one newly synthesized strand. The parental strands serve as templates for building the complementary new strands, so every daughter molecule ends up with a mix of old and new material. This result was shown by experiments that tracked old versus new DNA strands.

Think about what this implies for the other ideas: producing two entirely new strands would be a fully conservative model, which isn’t how DNA actually duplicates. Copying DNA is not the same as transcribing DNA into RNA, which is a separate process that makes RNA, not DNA. And replication doesn’t occur on just one strand; both strands are copied, though the synthesis on the two strands happens in different modes (continuous on one, discontinuous on the other) to form complete new double helices.