Well, basically within our cell we have this complex of special proteins and special RNA molecules that aggregate and combine together to form a complex, a structure known as a splicosome. And the splicosome is responsible for essentially locating these introns, removing the introns while at the same time gluing together splicing together those exons. And this can be seen in the following diagram. Now on top of essentially removing the introns these mRNA molecules in our cells and other eukaryotic cells are modified in two other ways. We basically cap the beginning with a special type of nucleotide sequence and that's called the capping process. And at the end of that mRNA we add an additional sequence that consists of a polyadenosine nucleotides as shown in the following diagram and we'll discuss what that means and what that is used for in more detail in a future lecture.