Question

Match the following genes of the Lac operon with their respective products.

a.	i gene	i.	$\beta -$galactosidase
b.	z gene	ii.	Permease
c.	a gene	iii.	Repressor
d.	y gene	iv.	Transacetylase

• A. a-iii, b-iv, c-i, d-ii
• B. a-i, b-iii, c-ii, d-iv
• C. a-iii, b-i, c-ii, d-iv
• D. a-iii, b-i, c-iv, d-ii

Answer 1

The correct option is D a-iii, b-i, c-iv, d-ii

The lac operon consists of:

• the regulatory i gene which codes for the repressor of the lac operon. The repressor binds with the operator gene in the absence of lactose and suppresses the transcription of structural genes.
• The lac operon has three structural genes: lac z, lac y and lac a. All three structural genes produce enzymes that are essential for the metabolism, entry and breakdown of lactose into its smaller monomeric units, glucose and galactose.
  • Structural gene z codes for beta-galactosidase, which is essential for the hydrolysis of lactose into galactose and glucose.
  • Structural gene y codes for permease. Permease increases permeability of the cell to β-galactosidase.
  • Structural gene a codes for transacetylase.