Question

What is a major disadvantage to a bacterial cell of having an operon?

Answer 1

Operons:

1. The cluster of genes found on a chromosome that is regulated by a single promoter.
2. For example- In the lac operon model, the lac operon has genes governing the regulation and uptake of lactose sugar.

The disadvantage of having an operon:

1. The bacterial system can be altered easily if there is any mutation in operon functioning which could lead to cell death.
2. Any mutation in the promoter or operator region can cause a change in normal functions due to which bacterial cell mechanisms will alter.
3. In any case, if this operon is mutated lactose metabolism will be altered in the whole which will be dangerous for bacteria.
4. In the case where glucose is absent and bacteria is dependent on lactose uptake, the lac operon is switched on.
5. Lac operon has a promoter sequence where RNA polymerase bind to synthesize enzymes needed for lactose degradation.
6. The operator region bind to the repressor sequence which stops the enzyme production whenever lactose is absent in the surrounding or glucose is present.

In case any of the genes in the operon model is mutated the process changes as:

1. If the promoter is mutated, RNA polymerase is unable to bind to it and hence there will not be any transcription.
2. In case of mutation in operator sequence, there will be a nonstop synthesis of lactose degrading enzymes as repressors cannot bind here which will lead to death to the cell.
3. Mutation in lac z, lac y, and lac a region will lead to the faulty synthesis of enzymes.
4. Thus any single mutation in the operon model affects the whole mechanism of bacterial cell uptake and metabolism.