When E. coli is exposed to both lactose and glucose, the organism first metabolise glucose and then temporarily cease to grow until the genes of lac operon become included to provide the ability to metabolise lactose. Allolactose is called an inducer because in its presence it turns on, or induces the expression of the lac genes. Related Theory When lactose is present outside the cell. it crosses the cell membrane and acts as an inducer of the operon. It does so once lactose is broken down to create allolactose. The lac operon is then membrane facilitating lactose transport into the cell, and & beta galactosidase, which eats up lactose to Make glucose molecules. And beta-galactosidase also makes allolactose. This leads to a positive feedback loop.
In an inducible operon, the genes are:
NEET UG 2013 — Zoology Molecular Basis of Inheritance
In an inducible operon, the genes are:
Held on 30 Apr 2013 · Verified 9 Jul 2026.
Options
- A
usually not expressed unless a signal turns them "on".
- B
usually expressed unless a signal turns them "off".
- C
never expressed
- D
always expressed
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