NEET 2026 (Phase 1) · BiologyPrevious Year Question
In the lac operon, the z gene codes for
Answer: (C) beta-galactosidase. Answer: (C) beta-galactosidase.
- A.permease
- B.transacetylase
- C.beta-galactosidase✓
- D.the repressor of lac operon
Correct Answer
(C) beta-galactosidase
Solution & Explanation
Answer: (C) beta-galactosidase. In the lac operon the z gene codes for beta-galactosidase, which hydrolyses lactose into galactose and glucose; the y gene codes for permease and the a gene for transacetylase, while the i gene codes for the repressor. NCERT Ch 5, p.100, lines 037-038: "The z gene codes for beta-galactosidase (β-gal), which is primarily responsible for the hydrolysis of the disaccharide, lactose into its monomeric units, galactose and glucose."
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