DNA translation
DNA translation is the term used to describe the process of protein synthesis by ribosomes in the cytoplasm or endoplasmic reticulum. The genetic information in DNA is used as a base to create mRNA by transcription. Single-stranded mRNA then acts as a template during translation.
What is DNA translation?
DNA translation is the process of converting the genetic information encoded in a DNA sequence into a functional protein. The genetic code is a set of rules that dictate how the sequence of nucleotides in DNA translates into the sequence of amino acids in a protein.
Translation begins with the binding of a protein called a ribosome to the RNA strand. The ribosome moves along the RNA strand, reading the sequence of codons (groups of three nucleotides) and translating them into the corresponding amino acids. The amino acids are then assembled into a protein according to the sequence specified by the RNA codons.
The genetic code
During translation, a cell reads the information in a messenger RNA (mRNA) and uses it to build a protein. To be a little more specific, an mRNA doesn’t always encode—provide instructions for—a whole protein. Instead, what we can confidently say is that it always encodes a polypeptide, or chain of amino acids.
In an mRNA, the instructions for building a polypeptide are RNA nucleotides (As, Us, Cs, and Gs) read in groups of three. These groups of three are called codons.
There are 61 codons for amino acids, and each of them is “read” to specify a certain amino acid out of the 20 commonly found in proteins. One codon, AUG, specifies the amino acid methionine and also acts as a start codon to signal the start of protein construction.
There are three more codons that do not specify amino acids. These stop codons, UAA, UAG, and UGA, tell the cell when a polypeptide is complete. Altogether, this collection of codon-amino acid relationships is called the genetic code, because it lets cells “decode” an mRNA into a chain of amino acids.