So let me get my pen tool out now, let me deselect this, get the pen tool out. At least for that section of, at least for that gene. So using the original right hand side, once again the T is paired with the A, let me do that in adenine’s color. And they kind of form these incredibly complex shapes and they have all of these functions. And what happens in transcription, let’s go back to looking at one side of this DNA molecule. And so let me copy and then let me paste. And replication, you can imagine taking either splitting these two sides of the ladder, and actually let’s do that.
So there we go, actually I didn’t wanna do that. It’s a new tool I’m using, so let me make sure I’m doing it right. Well you have one of four bases and you have them in three different places, so you have four times four times four, possible codon words I guess you could say. Or we would need to be able to replicate it. So let me write this down, so now you’re gonna have adenine pairs not with thymine but uracil. And they also, you might have more than one codon coding for the same amino acid. But this might just be this very, very small section, let me do this in a different color, this little section right over here, zoomed in.
And when you’re talking about a gene, you’re talking about a section of DNA that’s used to express a certain trait. And this process is called replication. So for example this might be a section of a much longer molecule, so the much longer strand of DNA, and even there I’m probably not giving justice to it.
And actually that warrants a little bit of a detour because you hear sometimes the words DNA and chromosome and gene used somewhat interchangeably, and they are clearly related, but it’s worth knowing what is what.
DNA replication and RNA transcription and translation (video) | Khan Academy
Molecular structure of RNA. And these proteins are essentially the molecules that run life for the most part. So there we go, actually I didn’t wanna do that. Proteins are made up of sequences of amino acids. Actually let me write this down. Thymine pairs with adenine, so thymine, adenine. So when you’re talking about DNA you’re talking literally about this molecule here that has this sugar phosphate base and it has the sequence of base pairs, it’s got relpication double helix structure, and so this whole thing this could be a DNA molecule.
So maybe I’ll do the new sugar phosphate backbone in yellow.
And replication, you can imagine taking either splitting these two sides of the ladder, and actually let’s do that. Or we would need to be able to replicate it. Now when you have a DNA molecule and it’s packaged together with other molecules and proteins and kind of given a broader structure, then you’re talking about a chromosome.
Let me write that down.
DNA structure and replication review
Intro to gene expression central dogma. And we actually haven’t drawn the next codon after that ’cause we need three bases to get to the answrs codon.
And so it’s very similar except for when we’re talking about RNA, adenine, instead of pairing with thymine, is now going to pair with uracil. Thymine pairs with adenine Let me do that a little bit neater. And as you put these repication acids together, then you’re actually constructing a protein. And four times four times four is The DNA molecule can be tens of millions of base pairs long.
And they also, you might have more than one codon coding for the same amino acid. And they kind of form these incredibly complex shapes and they have all of these functions. And so let’s see what that actually looks like. And one of the functions that RNA plays is to be that messenger, that messenger between a certain section of DNA and syntuesis of what goes on outside of the nucleus, so that that can be translated into an actual protein. And so three bases together, so these bases right over here, these I guess you could say this three letter word or this three letter sequence, syynthesis called a codon.
And so now that thing can leave the nucleus, go attach to a ribosome, and we’ll talk more about that in future videos exactly how that’s happened, and then this code can be used to actually code for proteins. Ribonucleic acid, let me write that down. So let me write this down, so now you’re gonna have adenine pairs not with thymine but uracil.
So how does DNA replicate?
So I’ll write this as “expression”. So this might be part of a gene Actually whoops, let me make sure I’m using the right tool. So cytosine just like that. Replicatiion actually used to code for a certain type of protein.