Nucleic Acids

[Music] hi it's Mr Anderson and in this podcast I'm going to talk about nucleic acids when I talk to students about nucleic acids they're confused they don't know what they do and they don't usually know what they're made up of they do know that their DNA and RNA but let's start with what they do and so the biggest job the DNA and RNA have is making the proteins the proteins inside the cell and so when you look at me you're looking at the protein prots but where are the directions to make those proteins those are

found in the DNA and how do they get to the proteins well they're shuttled out by RNA and RNA is more of a worker that's making these proteins inside the ribosome and so the first job they have is making proteins what's the second thing they do well they make up our genes and so that's what we pass on to the next generation and so this is my son he contains half of the DNA that I do so I gave him a random half of my DNA and my wife did the same so is a combination

of of me and my wife um and life has just passed DNA down generation after generation after generation we've never found life on our planet that doesn't have DNA that means that we're all connected through this single thread back to that first uh Universal common ancestor but what are they made up of those are nucleotides and so these are the building blocks of DNA and the building blocks of RNA so let's look specifically at one so this is one nucleotide right here a nucleotide is made up of three parts we've got a phosphate group that's

going to be pictured right here it's an phosphorus in the middle and then oxygen around the outside phosphate groups are really uh famous in biology so they're the phosphates that are found in phospholipids that make the cell membranes of all life and it's the same phosphate that we're going to find in ATP adenosine triphosphate it's the energy source and in fact the Aden adenosine triphosphate is exactly the same adenosine triphosphate that we add to make DNA we'll get to that in just a second what else do we have well we have a Pento sugar Pento

Sugar means we have a five carbon sugar in DNA that's going to be deoxy ribos sugar and then in RNA it's going to be a ribos sugar and then the most interesting part of a nucleotide is going to be the nitrogenous base and it's called a nitrogenous base because it has nitrogen and so most things in life are made up of carbon but there's going to be a lot of nitrogen here in the base of this nucleotide and this is going to be different in each nucleotide and so let's take a look at the the

nucleotides found in DNA and so basically you have adenine cytosine guanine and thymine and so we have four different bases and therefore we have four different nucleotides and you can just see looking at them the size is going to be a little different on the on all four of these um in RNA they don't have thyine you might know this but they have uracil it's going to look a lot like thyine but it's not going to be thymine if we to now look at all those nucleotides together so AC G and T and that's where

the names come from in DNA we're talking about these nitrogenous bases or these nucleotides and now we've got uracil basically if we put them in order by their size we've got two major groups we have these ones that have two rings and we call these purines so this is adenine and this is going to be guanine and then we have the peridin and they're just going to have one ring so cytosine thyine and uracil are all going to have one ring so they're going to be small smaller and that'll become really important when we start

bonding them together so let's talk about bonding how do you connect them together well when we talked about carbohydrates there's really only one way to connect carbohydrates or when we talk about amino acids there's really only one way to connect them but especially when you get to DNA you can connect nucleotides in two ways so let's start with way one way one we can put this one right underneath it so we got an adenine and a guanine and then through a dehydration reaction we could lose a water right here and we could form a coal

bond between two nucleotides and so if we were to add another one we would add another nucleotide here we lose a water and we're going to make another coal Bond and so we can attach them together like that and so that's what RNA is RNA is a number of nucleotides simply in a row and they're connected with calent bonds between each one there's another way however when we get DNA that we can we can Bond them and so let's say we have these two nucleotides Adine and guanine um how could I attach this thyine right

here well basically I can turn it upside down down and it's going to form hydrogen bonds here between the adenine and thymine and you've probably heard this before that adenine will always Bond uh to thyine and guanine will always bond to cytosine and that's why there's going to be interactions between the oxygen nitrogen and the hydrogen and make these hydrogen bonds that are con connect the two and so when you're looking at DNA let's kind of switch to this next slide when you're looking at DNA that's what's being connected right here in the middle so

that's going to be the those hydrogen bonds between the nitrogenous bases on either side and so why do we have DNA well we think life started with RNA because it contains a message but over time we kind of had two rnas wrap around each other and we eventually had DNA there's more to it than that but DNA is going to be a more stable structure we're going to have these hydrogen bonds here and then we're going to have hydrogen bonds between different um backbones of the DNA as well and so what are the backbone of

DNA really made up of it's just a sugar attach to a phosphate to a sugar to a phosphate to a sugar and so what are some differences between DNA on the right and RNA on the left well the first one would be the uracil versus the thyine so that's going to be a different nitrogenous base DNA is going to be a double helix and RNA is going to be a single Helix and then in life DNA is going to be found in the nucleus and RNA is going to be found pretty much everywhere that we

need it so if you're confused on how we go from DNA to proteins or if you're really interested in the whole secret of life I'll put a little uh link to a video I made that kind of talks you through how we go from DNA to proteins but the last thing I wanted to leave you with is how important they are if you're interested in RNA and if you're interested in science and video games then you may want to check this out this is Eterna Eterna is a video game uh I think it's centered at

Stanford University and basically what they're doing is they're letting people on the internet build sections of RNA and so basically you build sections of RNA um they have competitions each week and basically the winners each week they will make your RNA so they'll actually synthesize and make your section of RNA and then they'll see how it does and so I'm going to launch the video game and tuck you through the first level and uh if you're interested in in RNA or making things real in Biochemistry you may want to give this a okay so here's

level one basically it's a tutorial so I can click on next and it'll talk me through what I'm going to do so you're going to build your own RNA let me click on the next one RNA is made up of four bases hopefully you know what that means now yellow Bas is adenine guanine uracil and cytosine and so as a warm-up drill let's convert all the bases to guani so let me click here to start so basically what you can do is go down here I'm going to get my mutate and I'm going to mutate

this to guanine I love the music in here the little sound effects nice so I cleared level one and then you can go to the next puzzle and we can just going through and so BAS basically on this one what you can do is they will attract each other so for example they're going to say that adenine and uracil are going to come together and the guanine and cytosine are going to come together and so basically what you do is you get to play around with pairing these and so I'm going to stop playing the

video game in front of you but give it a look it's a really cool idea people competing to make RNA and then they're actually building it in the real world and so that's uh nucleic acids incredibly important and I hope that's helpful