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Chapter 18: Q18.1-3CC. (page 368)

A certain mutation in E.coli changes the lac operon so that the active repressor cannot bind. How would this affect the cell鈥檚 production of beta-galactosidase?

Short Answer

Expert verified

The repressor is the molecule that can regulate the working of the lac operon when it is not necessary. The mutation of repressor can result in the wasting of cell鈥檚 energy even when there is no lactose molecule for cell鈥檚 utilization.

Step by step solution

01

Definition of mutation

A mutation is a process that causes undesirable changes in the gene structure. It happens by deletion or addition of sequences within a particular genome.

The parts of the lac operon are lac I, lac Z, lac promoter, and lac repressor. The structural component works by switching the gene on and off.

02

Step 2: Activity of lac operon in the E.coli

E.coli can utilize lactose. The lac operon is the gene system that is responsible for using the lactose from the surroundings. The enzyme responsible for this metabolism is beta-galactosidase.

The structural segments that code for the enzymes are lac I, lac Z, lac promoter, and lac repressor, which can control operon activity.

03

Mutation to active the lac repressor

The mutation in the lac operator keeps the lac operon in an operational condition. It is due to the lack of binding of repressor to the operator region. The mutation changes the sequence of the lac operator, which will then accept the repressor molecules.

As a result, a cell will continuously produce the beta-galactosidase enzyme to utilize lactose in the absence of lactose. It results in wasting cell resources and energy for operating the lac operon.

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