 You know, if we are going to talk about the central dogma, we have to have some dogs to join us. And would you agree that perhaps this is the central dogma? Sorry. Okay, the central dogma describes how the information from the DNA gets made into a protein and it begins with DNA in the nucleus in the case of eukaryotes. DNA goes through a process called transcription. And yes, we will talk about transcription. The good news is transcription is actually very similar to DNA replication. So it's going to feel familiar. The result of transcription is the production of a messenger RNA molecule. So mRNA stands for messenger RNA. So DNA codes for the transcription of messenger RNA. And then the messenger RNA contains the instructions, the messenger RNA leaves the nucleus where transcription takes place and heads to the cytoplasm, I got there, where we get protein. And this process is called translation. Translation takes place in the cytoplasm. And in the case of eukaryotes, transcription takes place in the nucleus. Translation, we have a main kid, a main player, just like when we talked about photosynthesis, our organelle of the day was the chloroplast. And when we talked about cellular respiration, the organelle of the day was the mitochondria. When we talk about protein synthesis, really the organelle of the day is the ribosome. The ribosome is the organelle that takes that messenger RNA code, the instructions in the messenger RNA goes through the process of translation and produces a protein. How does transcription happen? Well, you don't have ribosomes in your nucleus that are making transcription happen, you rely on an enzyme. And I'm going to tell you the name of this enzyme, because it's should be familiar after we talked about DNA replication, we've seen this name before, the main enzyme that facilitates transcription is RNA polymerase. Okay, that's it. That's the central dogma. Now, a couple of thoughts about this. First of all, it's a complicated two step process, very molecular, very wild, very complicated, much more complicated than what we are going to have time or energy or capacity to talk about in this class. Why do we have two stages, especially like why in eukaryotes do we have two stages of this? Why can't we just take the DNA, the information from the DNA and take it to the ribosome to be translated into proteins? Well, the fact is, think about it a second. If you had to take an entire giant molecule of DNA and a whole chromosome of DNA out of the nucleus and into the cytoplasm, it's that is going to be an inefficient process. I often think of the DNA as like, I don't know, like a whole set of encyclopedias, like imagine the internet but printed. If you had a library, oh my gosh, back in the day, do you guys know this? Back in the day, we had libraries where you had to go there in order to get the information, you couldn't get information on the internet. And so you wouldn't, you'd go to the library. I remember doing this. I would go to the library, I would grab a book and I would take notes on the part that I needed. I didn't need to check out that entire massive book because usually there were like three pages that had the information that I wanted. And then I would take notes. That's what's happening here. The DNA doesn't have to go to the ribosome to produce the protein because we're just going to take the one recipe, the notes required to build just the one protein that we need in this situation. Then that messenger RNA goes out and it's little. And I say it's little. It's little compared to the entire DNA strand. Remember the DNA, like I don't know what was it, chromosome number one had like 4,000 genes on it. That means that it has 4,000 strings of DNA, pieces of DNA that code for proteins. But the amazing thing is that not all of our DNA codes for proteins. In fact, it's like 1% of our DNA that actually codes for proteins and the rest of it is regulatory. And we'll talk about that later in this section. But why take all that regulatory DNA out? Why take all that extra stuff when really all you need is that one example? I also think of it as like a recipe book and recipe cards. Like you copy the recipe you want onto a recipe card and then you take that to your kitchen and make the recipe, make the product, which is the meal. I would make cookies. I wouldn't make anything else. What about you? It's often helpful to come up with an analogy that works for you that helps you remember the central dogma. And it's always helpful to get pictures of dogs. There's a whole section on Wikimedia that is three dogs. So you can look it up and you can find like hundreds of pictures of three dogs. Okay, I'm going to go away and let's see what are we doing next. We're going to talk about transcription.