 So, nucleic acids. Nucleic acids are macromolecules that are polymers. Polymers means that their components are monomers and they have something in common, right? So, nucleotides are the monomers of the nucleic acids. The name nucleic acid comes from the fact that they were first isolated from the nucleus of the eukaryotic cells. However, nucleic acids are present outside of the nucleus as well. Now, this is the basic structure of the nucleotides. As you can see, what they have in common is a phosphate group, is a pentose sugar, sugar that has five carbon atoms and that pentose sugar could be deoxyribose in the case of DNA or it could be ribose in the case of ribonucleic acid or RNA. And nitrogenous base that is either one of these four for DNA or uracil in the case of ribose together with adenine, guanyin and cytosine for RNA. You have heard about DNA as base of life on earth and RNA as well. Let's see what are the differences between them. So, double helix is the feature of the DNA in most of the cases. The exception to the rule are some viruses that may have a single strand DNA. Ribonucleic acid in most of the cases are single-stranded. However, some viruses have double-stranded DNA and sometimes in our own body, like for instance, transfer RNA and have parts that are double-stranded. This is how they're pairing. So, timing and adenine, they are forming two hydrogen bonds between them. Guanyin and cytosine are forming three hydrogen bonds between them. The rest of it is a sugar phosphate backbone. So, how they're paired is that these are the bonds that are making the polymer and the three are bases that are there to combine with other strand. And we will learn more about it during the translation and transcription process, how it works. Cell's mother tongue is truly bilingual. What is happening here? You can see that this is DNA. How can you recognize T? Correct? This is RNA. You can recognize your acyl. So, DNA is basically instruction, book of instructions in our nucleus. And as any other book of instructions, if you want to make something, you're not going to tear off that page from the DNA. You will most likely go and photocopy the information that is in the book of instructions and just take that copy to go and make whatever you wanted to make from it. Correct? That is pretty much a situation that is happening in our cells. So, we have book of instructions, which is DNA, that gets separated during the reading of those or copying of that information that is needing for the instructions. That this process is called transcription. So, the language is the same, the language of nucleotides. How is that translated to the language of the amino acids or the language of the proteins is that three of the nucleotides are forming the codon? Codon. Chemically, remember, everything is about the shape. When this shape of these three bases in a row is recognized, then transfer RNA will bring serine as amino acid to the spot that is supposed to be there. And of course, you can see that it's reflecting the DNA information that was in the DNA. So, this process is called translation because it translates from language of nucleotides to the language of amino acid. All that is happening on the ribosomes that look like this. And you see here the input of the mRNA, which is the category of the ribonucleic acid. Each of the monomers of the amino acid is brought by tRNA and inside of the ribosomes, we have another category of the RNA, which is called ribosomal RNA. And that is where the translation process is happening. Now, let's see what can happen if we have something that is changing. So, in the case that we have mutation. Mutation means that during the process of the copying of the DNA, something went wrong. And that is happening normally in a certain rate, like one in every 100,000 of the nucleotides doesn't get properly fit together. But for instance, if here, during the process of the copying of the DNA, we have a situation that it changed from one letter to another. So instead of having, say like here, a tryptophan, this may lead to stop codon, which means that here the formation of the polymer of the polypeptide is going to be stopped. Obviously, that will lead to the incomplete polypeptide, which can lead to different problems in function or just different forms of the proteins that can bring to diversity in the life itself. That's what we all about nucleic acids. Thank you.