Here's why:
* Introns are sections of DNA that do not code for proteins. They are transcribed into RNA but are then spliced out before the RNA is translated into protein.
* Exons are the coding portions of DNA that are ultimately translated into protein.
Think of it like this: You have a recipe for a cake (the DNA). The instructions for making the cake itself (the exons) are interspersed with notes that tell you what ingredients not to use (the introns).
