In this video, we're going to begin our lesson on the steps of translation. Similarly to transcription, the process of translation also consists of three steps, and they are named the same as in transcription. It starts with the initiation process, moves on to the elongation process, and lastly, it concludes with the termination process. As we move forward in our course, we're going to talk about each of these three steps of translation in their own separate videos, starting with the initiation process.
In the initiation of translation, initiation means the start or beginning of the process. During the initiation of translation, the small ribosomal subunit of the ribosome first binds to the messenger RNA and a tRNA before the large ribosomal subunit even comes into play. If we look at our image at the initiation of translation, you will notice that initially, the small ribosomal subunit binds to the messenger RNA (mRNA) first, and then associates with the tRNA. Therefore, the sequence of events here is: the small ribosomal subunit binding to the mRNA, then the tRNA, and finally, the large ribosomal subunit is the last component to come into play during initiation.
One important note is that the mRNA contains the codons, which are three-nucleotide sequences. The very first codon is known as the start codon. The start codon is AUG, which specifies the amino acid methionine or MET. The start codon AUG, specifying the amino acid methionine, initiates the start of translation during this initiation process. In the mRNA, we have the codon AUG, which is the start codon. Codons specify amino acids through the tRNAs, which have anticodons complementary to the codon. The tRNA is a charged tRNA attached to an amino acid, which, corresponding with the start codon, is methionine (abbreviated as MET). This is the first amino acid in the polypeptide chain.
The initiation of translation can be quite a complex process, involving several proteins called initiation factors, which are not shown in this image. Translation during initiation requires energy, which is also depicted here to remind you that it requires energy. Ultimately, at the end of the initiation of translation, we have the complete intact ribosome bound to the messenger RNA and the very first tRNA corresponding with the start codon and the amino acid methionine.
This concludes our introduction to the initiation of translation and the steps of translation. We will be able to talk more about these steps as we move forward in our course, continuing with elongation and ending with termination. I'll see you all in our next video.