What component of mRNA is expressed in the final protein product?

The correct answer is exons, as they are the segments of mRNA that are expressed in the final protein product. During the process of transcription, the entire gene is initially transcribed into a precursor mRNA that includes both introns and exons. However, introns are non-coding regions that are spliced out during RNA processing, leaving only the exons.

Exons contain the actual coding sequences that dictate the amino acid sequence of the protein. When the mature mRNA is translated by ribosomes, the exons are read in groups of three nucleotides known as codons, which correspond to specific amino acids. This sequential process ensures that only the exons contribute to the final protein structure.

The other options, such as introns, codons, and anticodons, serve different roles in the broader context of gene expression and translation. Introns are removed before translation, codons are merely the triplet sequences that correspond to amino acids during translation, and anticodons are part of tRNA molecules that match with codons but are not components of the mRNA itself. Understanding the function of exons is crucial for grasping how genetic information is translated from DNA to functional proteins.