Exon

Definition

An exon is a segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence. During RNA splicing, exons are joined together to form the final messenger RNA (mRNA).

5 Must Know Facts For Your Next Test

1. Exons are sequences that remain in the mRNA after splicing.
2. They are expressed regions that code for proteins.
3. Exons can be found in both eukaryotic and prokaryotic organisms.
4. Mutations in exons can lead to changes in protein structure and function.
5. Alternative splicing can result in different combinations of exons being included in the final mRNA.

Review Questions

• What is the role of an exon in mRNA processing?
• How do exons differ from introns?
• Why are mutations in exons significant for protein function?

Related terms

intron:

A non-coding region of a gene that is removed during RNA splicing.

spliceosome:

A complex responsible for removing introns from pre-mRNA.

alternative splicing:

The process by which different combinations of exons are joined to produce multiple mRNA variants from a single gene.