In this video, we're going to talk about the second step of transcription, which is the elongation of transcription. And so elongation is really just a word that means to elongate or make something longer. And the something that's being made longer is the RNA itself. And so elongation is the process where the RNA polymerase enzyme is building or synthesizing or elongating an RNA molecule. And so it does this by base pairing free RNA nucleotides that are floating around in the cell with the DNA template.
And so by the end of the process, the RNA molecule that's being built is going to be carrying the message that's encoded by the DNA. Now the RNA polymerase enzyme, which is, again, the primary enzyme involved in transcription, is going to continue to move across the gene, unwinding the DNA as it moves and building the RNA as it moves in the 5 prime to 3 prime direction of the RNA. And so if we take a look at our image down below at the elongation of transcription, you can see that the RNA polymerase enzyme, this big pink circle, is now bound to the promoter region on the DNA, and, the RNA polymerase has unwound the DNA. So you can see that the DNA on the inside is unwound, and it's beginning to elongate or build that RNA molecule by pairing free RNA nucleotides, these little guys here that are floating in the cell, each of these little squares represents free RNA nucleotides, and the RNA polymerase incorporates them into this growing RNA strand, by pairing these RNA nucleotides with the DNA template strand. And so this RNA polymerase is transcribing in this direction towards the right, so it will continue to transcribe the coding sequence.
And so, this is representing the process of elongation. And, of course, during elongation, the mRNA, the molecule, RNA molecule is growing. It is elongating. And it's elongating from its 5 prime end to its own 3 prime end. And the RNA polymerase will continue to elongate in this direction, continue to transcribe the gene until it reaches this terminator sequence that you see on the end here.
And we'll talk more about this termination process in our next video. Now one thing that's important to note here is that in eukaryotic organisms, the RNA that is first transcribed is not the final RNA. Instead, it's a premature RNA or just a pre-mRNA. And so we'll get to talk more about the pre-mRNA later in our course. Now it's also interesting to note that a single gene can actually be transcribed simultaneously by several RNA polymerases to make more RNA if it's needed.
And so while this mRNA here is being built by this RNA polymerase, it is possible for a second RNA polymerase to come and bind to the promoter and to transcribe this gene simultaneously where there's multiple RNA molecules being built simultaneously from the same gene. And so, that is just simultaneously from the same gene. And so, that is just something to keep in mind. And so this here concludes our brief introduction to the elongation of transcription. And so in our next video, we'll get to talk about the 3rd and final step of transcription, which is the termination of transcription.
So I'll see you all there.