What’s up friends, how are you? Well, today we will see what proteins are. As we know, people tell us to eat proteins to be healthy, and proteins are generally found in meat and that sort of food. But, sometimes we just do not know why proteins are so important in our bodies to be alive, I mean, why they are so important for our cells so that they can be working. Well, we will see it in this video. Well, our body, as we know, is made of millions and millions of cells. All living beings, animals, plants, human beings, all type of living beings are made of millions of cells, So, such cells, in order to be able to live, reproduce, eat, grow etc., require of some very important things that without them, they could not live. Cells need PROTEINS. Proteins are like mini workers and live within their city, within their planet. Such planet is the cell. So, inside the cell there are too many mini workers, I mean, proteins, too many proteins. Each mini worker / mini protein is going to have different activities and roles. So, these proteins are divided into two types: structural and biological activity. About structural proteins, their only task is to shape the structure of a cell. Remember that cell membrane (wall cell) is made of a huge amount of proteins. In fact, too many things inside a cell are made of too many proteins. So, once this proteins are created, they use to go to cell walls (membranes), and then, they join together so that they can form the cell membrane. The other type of proteins (the ones of biological activity) are enzymes and antibodies. When we eat food, and it enters into the cell, enzymes will start acting over food so that they can obtain energy. I mean, to metabolize the food. Enzymes creates our metabolism. I mean, the eaters basically. Antibodies will protect us against any antigen, I mean, any disease like virus, bacteria etc. So ALL OF THEM ARE PROTEINS and all of them live inside the cell so that the cell can grow, reproduce and live. Without proteins, cells could not live. Therefore, we could not live. That is why they are very important. Well, now that we know the basis (the role of proteins within our bodies), we will see then how they are molecularly shaped, I mean, they molecular structure. and also how they are created. Well, these 3 types of proteins are almost the same in terms of molecular structure. They are different in some points, to have different roles, such as antibodies to protect us, enzymes to “eat” food, and structural proteins to join together and form the cell membrane. They vary a little, but are almost identical in terms of molecular structure, I mean, the way they are shaped. So, what we will see now applies to all proteins. In other moment I will then make a video for each one (enzymes, antibodies and structural proteins), detailing their little differences. OK, let’s continue… Well, proteins are like big balls as we can see in this image. This weird ball is made of many tiny threads, which are called peptidic chains. So, if we start unrolling the ball, we will see that they are too many tiny threads that were all bound together. Such peptidic chain has many little circles. Those little circles are called amino acids. We are only disassembling the protein in order to know how it is shaped. Once we unroll the protein, this image is exactly the same to this image here. Both are protein chains, but as always, scientists feel laziness to write atom by atom as shown in this image, and better they summarize and represent it like this, but it is just the same. The difference is that here it is shown atom by atom in comparison with here that is already summarized, just little balls and sticks. Okay, then, as we saw, a protein is basically a group of amino acids. Now, there are 20 natural amino acids and 2 synthetic amino acids. You can play with them in the position you want to create different proteins, and such amino acids are valine, leucine etc. There are 20 different names as shown in this table. And, If those amino acids are put in a different order (for instance, valine, leucine, isoleucine etc), this creates a protein. Likewise, if you change the order, this will create another protein. Now, if I create 50 amino acids, I will be creating a protein. And if now I create 70, 80 or 90 amino acids, different proteins will be created. So, playing with the position of amino acids and with the number of them, you can create thousand different proteins. Now, as we already know, a protein is made by many amino acids. So, from 2-10 amino acids will be called oligopeptide. “aa” means amino acids. From 10-100 amino acids are called polypeptide, and more than 100 amino acids are called proteins. Those amino acids will have different characteristics. Some will be more hydrophobic and others will be more hydrophilic, which means that some will be able to mix with water and others will not be able to do so, to dissolve. Some amino acids will be more acid, I mean, they will have positive charge, and other amino acids will be more basic, I mean, more alkalines, they will have negative charge. They all will have different functions, each amino acid has different features. All of those amino acids have something in particular, something that is identical in all of them… and this is the atoms you are seeing in red circles. Those atoms are the same that I have written now here in my blackboard. This is the basic structure of each amino acid. So, as we see here, we have a carbon in the center which is called alpha carbon. In the upper part, we have a hydrogen (and H). In the left we have one amino group (NH2), and in the right side we have a carboxyl group (COOH). So, this is present in all amino acids. In the down part, R means radical but also residue and this is the variable part of amino acids. So, this is the part in which all amino acids are identical, and here in this R is present the special characteristic of each amino acid. For example, some of them will be like this, and a C here and another C here, or perhaps others will have an S or H and so on, the 20 or 22 amino acids will be varying in the R part. So, if we form many of this structures like this in a row, we will create the protein. That is what I am showing here, if we put various amino acids in a chain form, we start creating the protein, as we saw it in the figures. And by binding the same molecule, I mean, by binding of carboxyl group with amino group, a peptide bond. This bound is called peptide bond. Here there is a peptide bond, here there is another peptide bond, and this is how peptide bonds are created. The creation of this peptide bond, I mean, carboxyl group with amino group, a new group is created which is called “amide group”. This is very important, so please remember it well, peptide bound creates a group called “amide”. And there are 4 structures that need to be followed to create the protein we already know. The first one is the primary structure where the linear chain is found, the long chain of too many amino acids as we see here. Then we have secondary structure. These long chains are created in 2 different ways: alpha helix which is like this, in helix form, that is why it is called alpha helix, in spiral form. The other is called beta sheet. Then, in the tertiary structure, once that alpha helix and beta sheet structures were already created, both start joining together, I mean, once that many were created, they start to join like this, like forming a weird ball, and this is the tertiary structure. Finally, in quaternary structure, many of those balls start binding each other, and they all together create the protein. That is the quaternary structure and this is how a protein is created. Now to finish, how proteins are created? Well, this occurs basically thanks to 2 processes called transcription and translation, which you can see in this videos that I have already made. That is called protein synthesis. I mean, in a very rapid explanation, we have a cell and from its DNA arises a molecule that arrives to the ribosome, and then many things occur and then proteins are created. Now that protein was already created in the cell, then it decides what to be, whether it will be an enzyme, a structural protein or an antibody. Finally, the advantage is that the name of all proteins will have the termination “in”, like casein, hemoglobin, insulin, carnitine, all the proteins will have the termination “in”. This is a very easy form of knowing which are proteins, isn’t it? And the second and last thing is that the weight of a protein is measured in “daltons”. Just as our weight is measured in daltons, proteins’ weight is measured in daltons. For example, a protein of 1000 daltons let’s say is approximately this size, and a protein of 2000 daltos is like this, 5000 is like this and 10,000 daltos is giant. So, a protein is measured in daltons. Well my friends, this has been basically all, I hope you have enjoyed and if you have doubts or comments, drop them below please, and also in my Instagram or Twitter, in any of them I will answer you. Please subscribe and do not stop of watching more videos!