Answer: Each daughter molecule retains one parental strand and gains one new strand.
- A Both resulting daughter molecules consist largely of newly synthesized strands
- B Each daughter molecule retains one parental strand and gains one new strand
- C Half of the nitrogenous bases are conserved while the other half are replaced
- D Mainly one of the two daughter molecules contains any original parental DNA
Correct answer: B. Each daughter molecule retains one parental strand and gains one new strand
Explanation: In semiconservative replication, each of the two daughter DNA molecules consists of one old (parental) strand and one newly synthesised strand.
Helicase unwinds the double helix at the replication fork; one new strand (leading) is synthesised continuously toward the fork, while the other (lagging) must be made in short, separate Okazaki fragments because DNA polymerase only adds nucleotides 5'→3'.
Concept context
DNA structure, replication, transcription, translation, the genetic code, and gene regulation (lac operon). The single most important chapter for NEET molecular biology.