 Wouldn't it be lovely if that was it? We were done. And now we know everything that we would ever want to know about genetics and molecular biology. And we're done. Not even close. Like when I say that this process of protein synthesis is that easy? Like you totally just did it. Isn't it awesome? You made a protein, good job. There are so many things that are complicating in so many ways that DNA functions that don't have to do with protein synthesis but play a huge role in critter function. I've made a list of organisms and I've put them in order of like kind of perceived complexity. Like humans, of course, the most complex and amazing critter of all. Mouse, yes, also a mammal, complex and cool. Fruit fly, what? It's just a bug. Mustard plant, just a plant. Roundworm, another animal like a fruit fly but like just a tube, like cool. And a yeast single celled fungus and a bacterium like prokaryote, very primitive. Oh, yes. So you could look at this list and be like very human centric and think like we've put them in order of complexity. I then took some numbers of like what are some facts about their DNA? And this is really interesting. They do, their genomes become smaller. So you'll notice that as we move down this list the number of bases in their genomes, their whole genomes, all their total bases becomes smaller as we go. I just noticed that this is three billion so these must be haploid. This must be their haploid, like just one copy of all of their chromosomes. I was about to say all these critters are diploid but I don't know. I definitely know humans are diploid and mice are but all the animals are but I don't know about the plants and okay but anyway, we'll talk about that later I'm sure. If you notice the number of chromosomes that doesn't correlate with complexity. Like we have the most chromosomes but remember I told you about was it a lungfish that had 133? Oh no, I don't think I gave you those facts. I don't know where those facts are but there's wide ranging diversity in the number of chromosomes that a critter has and remember chromosomes are just complete molecules of DNA. Here's where it gets really interesting. The number of genes and again, what is a gene? It's a piece of DNA that codes for a protein or a messenger RNA. We have, look, this guy, who is that? The plant has 25,000 genes just like us and the mouse. The roundworm has 19,000 genes. It isn't that much less than the rest of us. Here's the key friends, non-coding DNA. Look how much non-coding DNA we have. I remember being in high school and hearing folks talk about, oh my God, we've discovered this junk DNA and it does nothing. We just have all this junk DNA hanging around. That's not a junk folks. That non-coding DNA is somehow correlated to vastly complex possibilities. Our non-coding DNA is between one, I mean, our coding DNA is between one and 2% of our entire genome and every single critter goes down from there in the ordering of complexity. It's weird to me that we have so much non-coding DNA until you start thinking about, well, what is that non-coding DNA actually doing? It regulates everybody else. So non-coding DNA regulates stuff. And I'm gonna tell you, for example, non-coding DNA can regulate a process called alternative splicing. Alternative splicing is where you take one messenger RNA and you mix and match what become introns and what become exons and you can produce different proteins from one DNA. Who tells you which messenger RNA to produce? Look, I've got three different messenger RNAs. In this case, we included all five exons. Here we left out one of the exons and here we left out a different exon. That is the same DNA gene regulating DNA told it which one to make? Regulating DNA doesn't code for proteins. So it used to be considered junk DNA, no longer. We do not call it that for sure. The other thing that is interesting is there are regions of DNA, again, non-coding. I'm gonna write it down here so I don't have to go to a new page called enhancers. Enhancers can increase or decrease the production of protein synthesis and in that way can cause different outcomes with the proteins that are produced. The take home message is that this is far more complex than we will ever get into and that's okay. In the next lecture, we're gonna look at some applications of these molecular processes. We're gonna look at how are we using them and how do we mess around with them and how do they help us? Oh my gosh, they help us. Okay, see you later.