Final answer:
A mutation in the exon region of a gene is most likely to be damaging to a cell because it directly affects protein synthesis.
Step-by-step explanation:
The student has asked about the region of a gene where a mutation is likely to be most damaging to a cell. The regions in question are the exon (1), the 3' untranslated region (2), the 5' untranslated region (3), and introns (5). Among these, a mutation in the exon is typically most damaging because exons are the coding regions of genes that are directly involved in the synthesis of proteins. Mutations here can alter the amino acid sequence of the protein, potentially leading to a dysfunctional or even harmful protein being produced. Mutations in the 5' and 3' untranslated regions or introns are less likely to be damaging as they do not code for the protein directly, although they are still important for gene regulation and mRNA stability.
A mutation in the exon region of a gene is likely to be most damaging to a cell. Exons are the coding regions of a gene that contain the instructions for protein synthesis. If a mutation occurs in an exon, it can alter the sequence of amino acids in the resulting protein, leading to a functional change or loss of function.