Final answer:
The retention of lacZ produces β-galactosidase, an enzyme that breaks down lactose into glucose and galactose.
Step-by-step explanation:
The retention of lacZ produces the enzyme called β-galactosidase. This enzyme is responsible for breaking down lactose into its component sugars, glucose and galactose. The lacZ gene is part of the lac operon, which is a cluster of genes that regulate the metabolism of lactose in bacterial cells. The retention of lacZ produces β-galactosidase, an enzyme crucial for lactose metabolism in bacteria like E. coli. This enzyme breaks down lactose, which is a disaccharide sugar, into its constituent monosaccharides, glucose and galactose, allowing the bacteria to use it as a source of energy and carbon. This process occurs within the lac operon, which is a set of genes that includes lacZ, lacY, and lacA. These genes are expressed, or turned into proteins, only when lactose is present and glucose is scarce. The lac operon also includes a regulatory gene, the lacI gene, which produces a repressor that can bind to the operator sequence and block transcription in the absence of lactose. However, when lactose is present, it is converted to allolactose, which binds to the lacI repressor, causing it to release from the operator and allowing transcription to proceed.