Exams › NEET › Biology

In Escherichia coli, lac operon is induced by

1. lactose
2. promoter gene
3. β-galactosidase
4. I-gene

Correct answer: lactose

Solution

In the lac operon, lactose (more precisely allolactose, derived from lactose) acts as the inducer by binding the repressor and preventing it from blocking transcription. The other options are not inducers: the promoter is a DNA site, β-galactosidase is an enzyme, and the I-gene encodes the repressor.

Related NEET Biology questions

• Which of the following is a transcription factor produced by a regulatory gene?
• Which of the following combination is false?
• Which scientist experimentally proved that DNA is the sole genetic material in bacteriophage?
• If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNA double helix in a typical mammalian cell is 6.6 × 10⁹ bp, then the length of the DNA is approximately
• Which of the following RNAs should be most abundant in animal cell?
• The final proof for DNA as the genetic material came from the experiments of:

⚔️ Practice NEET Biology free + battle 1v1 →