Question

What does "lac" refer to in the lac operon?

• A. Lactose
• B. Lactase
• C. Lac insect
• D. The number 1,00,000

Answer 1

The correct option is A Lactose

In lac operon, lac refers to lactose. Here, a polycistronic structural gene is regulated by a common promoter and regulatory genes. Such arrangement is very common in bacteria and is referred to as operon.

The lac operon consists of one regulatory gene (the i gene) and three structural genes (z, y, and a).

• The i gene codes for the repressor of the lac operon.
• The z gene codes for beta-galactosidase, which is primarily responsible for the hydrolysis of the disaccharide, lactose into its monomeric units, galactose and glucose.
• The y gene codes for permease, which increases the permeability of the cell to b-galactosides.
• a gene encodes transacetylase.