Answer: The z gene.
- A The i gene
- B The z gene
- C The y gene
- D The a gene
Correct answer: B. The z gene
Explanation: The z gene of the lac operon codes for beta-galactosidase, which hydrolyses lactose into glucose and galactose.
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.