Question

What does lac refer to in the lac operon?

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

Answer 1

The correct option is D Lactose

The lac operon is an operon responsible for transport and metabolism of lactose in Escherichia coli and other bacteria and carries the genes that codes for enzymes involved in lactose metabolism only. This makes option D correct; "lac" refers to "lactose". The lac operon has three structural genes. The lac Z gene codes for $\beta$-galactosidase which converts lactose into glucose and galactose. The lac Y gene that codes for $\beta$-galactoside permease which transports lactose into the cell. The lac A gene codes for $\beta$-galactoside transacetylase. It does not carries the gene for lactase, an enzyme that digest milk sugar.

Thus, the correct answer is option D.