 This first image that I showed you has the primary differences between DNA and RNA. You'll notice down here at the bottom, we have the DNA and the RNA. And you'll notice that the RNA, they're trying to show you that it's almost identical, but it's usually just one strand as opposed to that double strand. Do you hear how I'm, if we have to be careful of how we use the word strand, because this is definitely, oops, can't use that one. This is definitely double stranded. But a double stranded molecule of DNA is still one complete molecule of DNA. So this is one molecule and this is one molecule. But there are a couple of differences that we can actually just see right here. In fact, I would love you to look at this and go, okay, what differences do you see? Oh, it's like those things that used to do when you were a kid on the back of the cereal boxes. How many differences are there between these pictures? Do they're identical? No, they're not. Okay, RNA is single stranded. And I say that with, hmm, it can fold up and form all sorts of weird shapes and we're going to see those especially in the next lecture. DNA is double stranded. Okay, that's one of the big differences. What's another big difference? I'm going to like do this. Do you see it? RNA nucleotides have a base called uracil. Instead, uracil is a pyrimidine. It's almost just like thymine. It even forms a bond with adenine. So in RNA, if you see a uracil, it means it's going to connect with adenine because there is no thymine in RNA. If you see a uracil, you know you're looking at RNA because DNA doesn't have uracil. Important to remember that. That's a big one. There's one more significant difference between RNA and DNA. And it has to do with the name. Deoxyribo and ribo. What do you think is different? I hear you. I hear you shouting it out. RNA is made with ribose sugar. So our pentose sugar is ribose in RNA. And in DNA, we already said it was deoxyribose. How's that for me not having to write that word out again and again and again? That's it. Those and how weird. The DNA forms a very stable, humongous molecule that in eukaryotes stays in the nucleus. RNA. RNA is much more active. It can get out. It can get around. And it plays several really important roles in DNA function. All of this leads us to a conversation about DNA replication. And how does that happen? And get ready because we've got some molecules to talk about.