The eukaryotic gene Gen-100 contains four introns labeled A to D. Imagine that Gen-100 has been isolated and its DNA has been denatured and mixed with polyadenylated mRNA from the gene.

Label the introns.

Key Concepts

Introns and Exons

Introns are non-coding sequences within a gene that are transcribed into pre-mRNA but are removed during RNA splicing. Exons, on the other hand, are the coding sequences that remain in the mature mRNA and are translated into proteins. Understanding the distinction between introns and exons is crucial for analyzing gene structure and function.

RNA Splicing

RNA splicing is the process by which introns are removed from the pre-mRNA transcript, and exons are joined together to form the final mRNA molecule. This process is essential for producing a functional mRNA that can be translated into a protein. Knowledge of splicing mechanisms helps in understanding how gene expression is regulated.

Polyadenylation

Polyadenylation is the addition of a poly(A) tail to the 3' end of mRNA molecules, which enhances mRNA stability and facilitates its export from the nucleus to the cytoplasm. This modification is important for the maturation of mRNA and plays a role in the regulation of gene expression. Recognizing the significance of polyadenylation is key to understanding mRNA processing.