 Dear students, in this module we are going to talk about the amino acids. You know that amino acids are polymerized together to form proteins in a process called translation. RNA molecules that have the nucleotides within them, they dictate how these amino acids will be put together towards formation of a protein. These nucleotides, they act in nucleotide codons in which three nucleotides are present at a time. So three nucleotides, they code for one amino acid at a time. In all, there are 20 different amino acids that can be coded by the codons in the RNA. So if you have a codon with a different sequence, then it will code for a different amino acid. So total, there are 20 amino acids and any combination of the nucleotides arranged into a codon of three nucleotides can code for those nucleotides. Next we will see which codons are going to code which amino acid. As you can see here, if in an RNA molecule you have U, U, A or U, U, G in the sequence, then leucine that is the amino acid will be coded. Next following these codons, if there were another codon with CAU or CAC, the amino acid histidine will be coded. So now you have two amino acids coming together. Next, if you have a codon from any one of these four in the RNA sequence, then you will be coding for valine. So this will be your third amino acid. So in this way, your amino acids, they come together in a chain. And this chain is the beginning of the formation of a protein. In all, there are 20 amino acids and as you can see in this periodic chart of amino acids, the basic amino acids or the amino acids with basic properties are listed on this side here and the acidic ones are listed on this side. The rest of them, they have partially acidic and partially basic properties. Interestingly, the amino acids, they share a common structure. The commonality between these 20 amino acids is such that at one side of the amino acids, they have the NH2 or the amino terminal, while at the other side, they have the carboxylic group attached, carboxyl group. So this is the C term in short and this is the N term in short. So all others are differing, all the amino acids are differing here at what is called the R group. So basically, all the amino acids have an N term, they have a C term and they have an R group in which they are different. So this is how the amino acids, they are organized in their structure and how do these two amino acids, they come together as a result of the process in which a peptide bond is formed. So the process is highlighted here. So the C term of one amino acid gets attached to the N term of the other amino acid and water is released in the process while the two amino acids, they come together to form a dipeptide. So this is the polymerization of amino acids by formation of a peptide bond. Here the polymerization of amino acids, the amino acids, they fold into structures and therefore they become folded proteins. The folding of these amino acids chains is very important to impart function onto the proteins and once you have the proteins that are folded together and taking forms of different sheets and barrels, they are active within the cell. So now you have seen how an amino acid chain is formed and it gets folded which is then functionalized to perform certain functions within the cell. In conclusion, the proteins are polymerized after the amino acids, they come together and that they are chain together by the peptide bonds and the proteins they take 3D structures and forms that are important towards functionalizing these proteins.