NEET 1994 · Class 12

Molecular Basis of Inheritance

'Lac operon' in E. coli, is induced by

  1. (A)'i' gene
  2. (B)promoter gene
  3. (C)b2-galactosidase
  4. (D)lactose

The NCERT line that answers it

Verbatim line

Lactose is the substrate for the enzyme beta-galactosidase and it regulates switching on and off of the operon.

Chapter
Molecular Basis of Inheritance
Section
5.8.1 The Lac operon
Page
22
Words matched
38 of 38

The answer appears as a continuous sentence in NCERT. This is that sentence.

How this line gives the answer

0, emb=1.0, combined=1.0). Verified: high — The span explicitly states 'Lactose...regulates switching on and off of the operon' and 'it is termed as inducer,' which directly and conclusively identifies lactose as the inducer of the lac operon, matching the MCQ's correct answer.

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