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

Explain how genetic complementation contributes to the growth habit of this strain.

Key Concepts

Lac Operon

The lac operon is a set of genes in E. coli that are involved in the metabolism of lactose. It consists of structural genes (Z, Y, A) and regulatory elements (promoter P, operator O). The operon is controlled by the presence or absence of lactose, which influences the expression of these genes, allowing the bacteria to utilize lactose as an energy source.

Genetic Complementation

Genetic complementation occurs when two different genetic mutations in a diploid organism can restore a normal phenotype when present together. In the context of the lac operon, if one allele produces a functional protein while the other does not, the functional protein can compensate for the defective one, allowing the organism to grow under conditions where it would otherwise be unable to.

Partial Diploidy

Partial diploidy refers to a genetic condition where an organism has two copies of some genes but only one copy of others. In the case of the lac operon, the presence of both cap and I genes in different states (mutant and wild-type) allows for the study of gene interactions and complementation, providing insights into how these genes regulate lactose metabolism in bacteria.