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7. DNA and Chromosome Structure



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Hi in this video we're gonna be talking about R. N. A. So RNA differs from D. N. A. In a lot of ways. And one of the first ways that it differed is that it was scientists believe that RNA was actually the first genetic material used during the early world. And this is because RNA has certain qualities that DNA doesn't. And one of the major qualities is that R. N. A. Has the structure called Ribas. Symes and ribbons. Symes can actually catalyze chemical reactions, meaning they can act as enzymes without anything else. Just aren't a completely by itself. Can fold into these complex structures and act as enzymes and DNA can't do this. And so in order for a piece of genetic material to replicate and to you know divide and to be expressed, you have to have proteins, you have to have enzymes that can do that. And for D. N. A. We have those right, we have D. N. A. Polymerase which helps with replication. We have different types of transcription enzymes and so on and so forth. But RNA actually doesn't need any of it. It uses it because it has it. But RNA actually has bright designs. And RNA can theoretically do all of those things without anything else. And so because of this dysfunction to form these enzymes, RNA is believed to be the early genetic material of that early world now it's not as stable as D. N. A. And so we think our scientists believe that eventually you know, DNA evolved it was more stable. So it stuck around it became the main genetic material. But RNA was definitely likely the first type of genetic material on the planet. And so RNA structure differs from D. N. A structure. First, it has a Revo sugar instead of a deoxyribonucleic sugar. And the difference between the two is that a ribose sugar has a hydroxyl group at two fried carbon, whereas the D oxy ribose Has an H. at the two Brian carbon. And this small difference, right? It's the presence of an oxygen or not. Right? De oxy so uh lack of oxygen but this small difference, this lack of oxygen um or this presence of oxygen and ribose makes are in a much more easily degraded that oxygen makes it much more easy to react with things and become degraded than D. N. A, which lacks that oxygen. Now for the basis RNA contains an extra base called your cell but it does not contain timing and it sort of replaces the timing and RNA unlike D. N. A, is normally single stranded. So here's an example. This is actually A T. E. R N. A. You may be familiar with helps in translating proteins but essentially this is completely RNA. There's no protein here and you can see that there's this first it's folded up into this unusual structure here and the structure actually has a catalytic ability. So it can act as a as a tiny enzyme essentially to help during translation. So that gives RNA it's unusual quality. Now there are many other different types of RNA. S. So M RNA is we, what we say is the coding RNA. Because this is what's used to code for proteins. There are two RNA is important for translation. The R RNA, this creates the ribosomes and the T. R. N. A. Which is what I just showed you up here and this adds amino acids onto the poly peptide chain and will go over this whole process and other videos. But just sort of an overview. But interestingly enough, there are a lot of non coding RNA. So RNA is that don't create these um these Tr nasr RNA srm RNA um with a variety of functions. So we there's micro RNA s, which are M I R S. I R N. A. S. And these play a role in what's called RNA interference, don't necessarily need to know that. But essentially these are N. A. S play a major role in gene expression turning on and turning off genes whenever they're needed or not needed. So micro RNA S and S. I R N. A. S. They don't code for proteins, they just exist by themselves but they have major roles in gene expression. There are small cytoplasmic RNA s which we know exist but we don't know their function and there's tons of them no idea what they do. We've long non coding RNA is which again have many functions in gene expression, some in protein control or etcetera. So having some pathways, these can have a lot of different functions. Um, we have S. N R N A. S. These are important for converting pre M RNA. So the step before this, M RNA into M R N. A. These are super important. And then we have snow RNA, which process these RNA S. So there's tons of RNA is write some code for proteins. Right? These M R N A S, some are involved in processing, some are involved in gene expression, some have unknown function even though they exist but are nasr super important. It's not just DNA encoding for these proteins. RNA is do a lot of kind of the background work of the cell, making sure everything is working properly and being processed correctly. Um so that these proteins can be expressed at the correct level that they need to be so that we look like we do and we don't die. So our knees are super, super, super important and have always been super important. So with that let's now move on

True or False:RNA predated DNA as the main genetic material during the early world.


Which of the following is not a difference between DNA and RNA?


Which of the following terms is used to describe catalytically active RNA molecules?