Life Sciences DNA vs RNA | DNA PART 3 | Grade 10-12 | 2021

In grade 12, you learn about DNA and you learn about RNA, but sometimes in a test or an exam, they will test you to see, do you know how they are similar and how they are different? And that's what I'm going to tell you about now. This video is going to deal with similarities and differences of DNA and RNA. So let's look at the similarities first. The first thing is that they both have alternating sugar and phosphate molecules that make up the backbone of that ladder that makes up the double helix. The next thing is that they both have nitrogenous bases, but the nitrogenous bases that they have in common are adenine, guanine and cytosine. You'll notice thymine isn't here, uracil isn't here. That comes later. Okay, so the similarity is that they both got adenine, guanine and cytosine, and both are involved in protein synthesis. So there are three similarities that you need to know, and here they are. Now let's look at some of the differences. Sometimes in a question, a teacher will say, compare the differences between DNA and RNA. Now, whenever you get something like that, they say tabulate the differences between DNA and RNA. Now, if you have to tabulate the differences between two things, I always recommend that you make a third column like I have on the screen here. The first column is what you are comparing about DNA and RNA, and you'll see what I mean as we go along. It's really, really a good habit to get into, otherwise your marker or your teacher doesn't know what are you actually comparing, because you have to compare the same things every time. So now the first thing that I'm comparing there, is it single-stranded or double-stranded? DNA, we know, is a double helix, and RNA is a single strand. So that's how you would write it in there. The next one, the sugar present. They've both got sugars. We said that in the previous, when we looked at similarities, but now what sugars do they have? The one has, DNA has deoxyribose, that's where it gets its name from, deoxyribonucleic acid. It comes from the sugar that's present. And ribonucleic acid has ribose. So that's a difference. Another difference is that the fourth nitrogenous base, remember they all have adenine, and cytosine, but the fourth one is different. And in DNA it's thymine, and in RNA it's uracil. And you know that fact is the most important one, or the one that people make the most mistakes. When you start working and manipulating DNA and RNA and saying what it should be in questions, then guys forget or girls forget that thymine must actually be replaced with uracil, because we're talking about RNA. But when we speak about DNA, we have to speak about thymine. So remember that one. And then the last difference is where it's found. DNA is found in the nucleus, it's found in the cytoplasm, and in the mitochondria. You get nuclear DNA and you get extra nuclear DNA. And RNA is found in the nucleus and the cytoplasm. Now if you had to mention let's say three differences, I would mention the first three, unless they ask you to mention location. Don't start with location, rather start with the first three if you only have to mention three or two. So that's the basic similarities and differences and the ones that you need to know for your exams. If you haven't subscribed to this channel, then now's the time to do it, because then you'll have access to all my videos on life sciences and you'll be able to get the best marks possible. I also offer Zoom classes, so if you want to enrol for them, then just send me a message and I'll contact you and we can arrange that.