Which term describes the expressed sequence of DNA that codes for a protein?

Which term describes the expressed sequence of DNA that codes for a protein?

• A. Exon
• B. Intron
• C. Promoter
• D. Terminator

Answer: (A)

Exons are the expressed portions of a gene that remain in the mature mRNA and encode the amino acid sequence of a protein. In eukaryotic genes, the initial transcript includes both exons and introns; introns are removed by RNA splicing, and the exons are joined to form the final mRNA used as a template for translation. Promoters and terminators are regulatory DNA elements that signal where transcription starts and stops, not the coding parts of the gene. So, the sequence that ultimately codes for the protein is the exon.

Exons are the expressed portions of a gene that remain in the mature mRNA and encode the amino acid sequence of a protein. In eukaryotic genes, the initial transcript includes both exons and introns; introns are removed by RNA splicing, and the exons are joined to form the final mRNA used as a template for translation. Promoters and terminators are regulatory DNA elements that signal where transcription starts and stops, not the coding parts of the gene. So, the sequence that ultimately codes for the protein is the exon.