What is an mRNA codon?

1 Answer
Apr 2, 2017

A mRNA codon is a 3 base pair long part of the mRNA that codes for a specific amino acid in the ribosomes of a cell.


Cells make protein for many different reasons. A protein can, for example, be an enzyme or an inhibitor. The information to make this protein is stored inside the nucleus of the cell in the DNA (Deoxyribonucleic acid).

The way that this information is stored is by placing so-called 'bases' on a line. The information what to make and what to do is coded in the order of these bases. A single stranded DNA is showed below.
DNA is double stranded meaning that there are 2 strands with the same 4 bases coupled to each other (A-T and C-G)

To make the proteins DNA is transcripted into mRNA. This stands for messenger RNA. The base order of DNA is read by enzymes and a single stranded mRNA is made. mRNA differs from DNA in some aspects.

Now, this mRNA can leave the cell nucleus and travel to an organelle called the ribosomes. Here the mRNA is read and amino acids are made. Each 3 bases along the mRNA line codes for 1 amino acids. So you can have, for example, the bases ACC which codes for the amino acid Threonine.

It is pretty easy to find out which amino acids are created using the image below. http://www.chemguide.co.uk/organicprops/aminoacids/dna5.html

First, you chose a base at the vertical left. Then you selected the second base at the horizontal top, and then for the third base you select at the vertical right side. As you can see, some mRNA codons are coding for the same amino acid.

Amino acids are used to create proteins.