What is the difference between introns and exons, and how do they function in gene expression?

Introns are non-coding sequences of DNA, while exons are coding sequences that determine the protein sequence.

Introns are segments of DNA that do not code for proteins and are found within a gene. They are transcribed into RNA but are removed during the process of splicing, which produces the final mRNA molecule. Introns can be quite long and can make up a significant portion of a gene. They are thought to have evolved as a way of increasing the diversity of proteins that can be produced from a single gene.

Exons are the coding sequences of DNA that determine the amino acid sequence of a protein. They are transcribed into RNA and are spliced together to form the final mRNA molecule. The sequence of exons determines the sequence of amino acids in the protein, which in turn determines its structure and function.

The process of gene expression involves the transcription of DNA into RNA and the translation of RNA into protein. Introns play a role in this process by being transcribed into RNA but then being removed through splicing. This allows the final mRNA molecule to contain only the coding sequences necessary for protein synthesis. Exons, on the other hand, are the sequences that determine the protein sequence and are therefore essential for gene expression. Together, introns and exons play a crucial role in regulating gene expression and determining the diversity of proteins that can be produced from a single gene.