Question

Name the enzyme, which will be produced in a cell in which there is a nonsense mutation in the Lac Y gene?

Answer 1

β-galactosidase:

1. Francis Jacob and Jacques Monad postulated that metabolic pathways are regulated collectively while they were employed at the Pasteur Institute in Paris.
2. They looked at how the nature of E. coli enzymes changed when it was given different kinds of carbohydrates.
3. An example of an inducible operon is lac-operon, which is activated when the enzyme permease adds a few molecules of lactose to the cell.
4. When these molecules are together, lactose changes into an active form that binds to the repressor and prevents it from binding to the operator.
5. They discovered that when lactose is given to an E. coli culture, it produces the three enzymes needed to convert lactose to galactose.
6. These newly created enzymes include transacetylase, permease, and β-galactosidase.
7. They assert that a lengthy region known as an operon, which is divided into three structural genes Z, Y, and A, and an operator site O, is responsible for regulating the synthesis of three enzymes.
8. The operator site controls the activity of the regulator gene with the assistance of the structural gene.
9. Lactose/galactosidase is broken into glucose and galactose by the enzyme β-galactosidase, which is produced by the gene Z.
10. The lactose entry enzyme permease is produced by gene Y, and the galactosidase acetylase and transacetylase enzymes are produced by gene A.
11. Mutations are described as abrupt alterations.
12. A nonsense mutation is a type of mutation in which a single codon is changed, leading to the development of a stop codon that stops the synthesis of polypeptides.
13. A stop codon will be added to the sequence following the lac Z gene as a result of a nonsense mutation in the lac Y gene as the gene Z is transcribed before to the lac Y and lac A genes.
14. Therefore, just β-galactosidase will be generated, and no other enzymes.