Suppose the lac operon partial diploid cap⁻ I⁺ P⁺ O⁺ Z⁻ Y⁺/ cap⁺ I⁻ P⁺ O⁺ Z⁺ Y⁻ is grown.

Will this partial diploid strain grow on a lactose medium?

Key Concepts

Lac Operon Structure

The lac operon is a set of genes responsible for the metabolism of lactose in bacteria, particularly E. coli. It consists of structural genes (Z, Y, A) that encode proteins for lactose uptake and breakdown, a promoter (P), an operator (O), and regulatory genes (I). Understanding the operon's structure is crucial for analyzing how mutations or variations affect lactose utilization.

Partial Diploidy

Partial diploidy refers to a genetic condition where an organism has two copies of some genes but not others, often due to the introduction of a plasmid or a chromosomal fragment. In the context of the lac operon, this means that the organism can express alleles from both copies, which can influence the expression of the operon and its ability to metabolize lactose.

Lactose Utilization and Gene Expression

For a bacterial strain to grow on lactose, the lac operon must be expressed, allowing the organism to produce the necessary enzymes (like β-galactosidase) to metabolize lactose. The presence of functional alleles (like Z⁺) and the regulatory mechanisms (like the repressor protein from I) determine whether the operon is active, thus influencing the strain's ability to utilize lactose as a carbon source.