Which enzyme will be produced in a cell if there is a nonsense mutation in the lac Y gene?
Correct answer: C. β-galactosidase
- A. Transacetylase
- B. Lactose permease and transacetylase
- C. β-galactosidase
- D. Lactose permease
Explanation
A nonsense mutation is the one that stops polypeptide synthesis due to the formation of a termination or nonsense codon. In the lac operon, the sequence of structural genes is Z, Y, and A, which respectively code for b-galactosidase, lactose permease, and transacetylase. If the gene Y has a nonsense mutation, gene expression will stop at it, resulting in nonexpression of both gene Y and successive gene A. Thus, only the b-galactosidase enzyme will be produced.
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About Chromosomes
Chromosomes are DNA-protein structures that carry genes and become visible during cell division. Coverage includes chromatin, centromeres, sister chromatids, homologous chromosomes, chromosome number, and the distinction between diploid and haploid cells, with links to DNA replication, mitosis and meiosis.
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