Proteins

in this video, we're going to begin our lesson on proteins Now. Proteins are one of the major classes of bio molecule polymers that are made up of amino acid monomers, and so amino acids are the monomers that make up proteins. Now the co Vaillant bonds that link adjacent amino acids together in a chain are specifically referred to as peptide bonds, and we'll be able to see some examples of these peptide bonds down below in our image. But it's also important to note that the protein polymers are actually going to have directionality, meaning that in the chain of the protein polymer, one end is going to be chemically different than the opposite end. And so we refer to these ends as the end terminal end and the C terminal end. And so let's take a look at our example image down below at the formation of proteins from amino acid monitors to get a better idea of these concepts. And so notice over here on the far left hand side, we're showing you all of these separate individual circles, which represent amino acid monomers, and so these are amino acids that air separate from each other But of course, if we join these amino acid monomers together in a chain like what we see here, then we're building ourselves a protein polymer and notice that the protein polymer has directionality because on one end over here, it's chemically different than the opposite end over here. And so the end that has the amino group, like what we see over here, is referred to as the end terminal end because the amino group has a nitrogen atom. And then this other group that we see over here on the opposite end is referred to as the C terminal end. Because it has a car box Aled Group, which we see over here and then notice that each of these separate amino acid monomers are being co violently linked together through these bonds that we see right here. And these bonds that covertly lengthy a genome adjacent amino acids together are referred to as peptide bonds. And so this here really concludes our introduction to proteins. And we're going to continue to talk more and more about proteins as we move forward in our course. And so I'll see you all in our next video

in this video, we're going to talk some more details about amino acids now. Amino acids recall from our last lesson video are really just the monomers of proteins. And so linking together multiple amino acids allows us to build a protein polymer. Now each individual amino acid monomer is going to contain common components that are common to all amino acids. And then they're also going to contain some unique components, such as the unique our group, and we'll be able to see the common components in the unique our group down below once we get to our image. But living organisms, they primarily used a total of 20 different amino acids, and once again, these different amino acids. They all have common components that we're gonna talk about. But each of the 20 amino acids also has a unique, so each has a unique our group. So let's take a look at our example down below to get a better understanding of these ideas. So we're taking a look at the amino acid structure, and so over here on the left, what we have is a table of the amino acid components, and so recall in our last lesson video. We were representing amino acids using these circles. And so these circles, each of these circles has, uh, these components that we're talking about and these components you can see over here in a more detailed chemical structure of the amino acid. So each of these amino acids is going to have common components, which we have in the red box. So the red dotted box that you see here represent the common components that are found in all 20 of the different amino acids and down below. What you'll see is a green shading, which is gonna be the unique region of the amino acid that will differ between all of these 20 amino acids. So when we look at the common components, notice that it starts with the central carbon atom, which is also known as the Alfa Carbon. And so over here, when we look at the chemical structure, you can see that the central carbon atom is right here in the center, right in the middle. Now coming up off the top of the central carbon atom, we have a central hydrogen atom s O. That would be this hydrogen atom that we see here and again. This is a common component found in all amino acids and then going to the left and going to the right of the central carbon atom. We have these two functional groups that you should recognize. So going to the left over here in blue, what we have is an amino group, which is where the end terminal end would be for this amino acids. And then, of course, going to the right Over here in yellow, what we have is a car box Aled Group, which is going to be the C terminal end of the amino acid. And so once again, all of these components that we talked about here are the common components found in every single amino acids. And really, what makes one amino acid different from another amino acid is going to be the our group, the unique our group. And so we can put the our group here and the our group. You can pretty much think that the R stands for the R and the rest of the molecule because the our group is going to be variable. It will change from amino acid, two amino acid, and it represents the rest of the molecule. Some amino acids have a really, really small our group with just ah handful of atoms, just maybe one. Adam sometimes and other amino acids have our groups that are much, much larger in size and have many, many mawr atoms, and they're much, much more complicated. But the backbone this region here is going to be common for all amino acids, so that's important to keep in mind now for your biology class, you're likely not going to need to know all 20 of the different amino acids, but you will need to know that there are 20 and you will need to know the common components and the fact that they all have a unique our group that has different properties. And so this year concludes our introduction to amino acids, and we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you guys in our next video

So as you guys air reading through your textbooks or sitting in class listening to your professors, you might hear these five protein related terms just tossed around and used all the time. But not everyone distinguishes between these five protein related terms. And so here in this video we're going to specifically distinguish between these five protein related terms. And so these five protein related terms air referring to amino acid chains that very in their length and so notice down below. We have this table that has the protein related terms over here on the left hand side, and then it has the length of the amino acid chain over here on the right hand side. And so the first protein related term that you all should know is, of course, amino acid, which we already talked about in our last lesson video. So we already know that amino acids are a single protein unit, or, in other words, ah, monomer of a protein is an amino acid. And then, of course, we can take these individual monomers these individual amino acids, and link them together to create a long chain of amino acids. And that's where these other four terms come into play. So the second term that we have here is going to be Allah go peptide. And so recall that the AHL ago prefix means a few. And so Allah go peptides are going to have an amino acid chains that have just a few amino acids somewhere between about two and about 20 covertly linked amino acids in the chain. So pretty short amino acid chains are illegal peptide chains. Now the term peptide without the Allah go prefix is referring to amino acid chains that have less than covertly linked amino acids. And so what's important to note here is that Allah go peptide and peptide. At some point, there's a little bit of overlap between the two terms. Now the fourth term that we have here is poly peptide and recall that the prefects polly means many. And so these air going to be amino acid chains that have greater than 50 amino acids that air co violently linked together. Yeah, and then the fifth and final term that we have here is protein itself. And so a protein is specifically referring to just one or multiple poly peptide chains that air specifically, and they're folded or functional forms. And so when we're talking about proteins were talking about poly peptides that are in there folded or functional forms. And when we say folded, what we mean is that these chains don't just remain as straight linear chains. They actually fold up into themselves and create these complex, three dimensional structures. And so, really, this leads us to our next lesson video, which is talking about the levels of structure of protein. So I'll see you all there in that video.

in this video, we're going to introduce protein structure. And so proteins have a hierarchy of structure that's organized into four levels of structure that air conveniently labeled primary, secondary, tertiary and Quaternary levels of protein structure. And so notice that the text that we have up above for each of the four levels of structure corresponds with the image that we have down below for each of the four levels of protein structure. And so the very first level of protein structure is the primary level of structure, which we can abbreviate with a one here. And so the primary level of protein structure specifically refers to the types, the quantity and the specific order or sequence of amino acids in the chain. And so, by changing either the types, the quantity or the order of amino acids in the chain, then we can change the primary level of protein structure. And so the primary level of protein structure is really, really, really important because it determines all of the other levels of structure, including the secondary, tertiary and quaternary levels of structure. And so when we take a look at our image down below, over here on the left hand side notice that each of these circles represent amino acids. And so we have this long amino acid chain here and the specific types, quantity and order or sequence of these amino acids in this long chain eyes going to be the primary protein structure so we can fill in primary down below over here now the second level of protein structures, of course, the secondary level of protein structure, so we can put a two over here, and this is referring specifically to the formation of either Alfa Hillis ease or beta sheets in the protein backbone. And so when we take a look at our image down below at the secondary protein structure, notice that the protein backbone can either take a winding shaped like what we see here, which would be the Alfa Helix. Or the protein backbone could take more of a zigzag shaped like what we see down here, which is the beta sheet structure. So this is more of a zigzag, whereas this is more of a winding structure, and so we could say that secondary protein structure is going to be the formation of either Alfa he'll is's or beta sheets in the protein backbone, and so this leads us to the tertiary level of protein structure, which of course can be symbolized here with a three. And so the tertiary level of protein structure is specifically referring to the overall three D shape, or three dimensional shape of the poly peptide chain. And so, if we take a look at our image down below, notice that the long poly peptide chain over here, when it forms Alfa Hillis is in beta sheets. It can fold onto itself to create this complex, overall three dimensional structure. And so the tertiary protein protein structure. It's specifically referring to the overall three dimensional shape and so embedded within the overall three dimensional shape. You can see the Alfa Healy sees here that air in blue, and you can see the beta sheets that air in red over here. And so these levels of structure they build onto each other. And so this leads us to the fourth and final level of protein structure, which is the Quaternary level of protein structure, which, of course, could be symbolized with the four, and this is specifically referring to win Multiple poly peptide chains are going to associate with each other toe form a single functional protein. And so when we take a look at our image down below, notice that there are two poly peptide chains here we have this lighter gray poly peptide chain over here, and then we have this darker poly peptide chain over here. And when you have these two separate poly peptide chains that come together and associate to form a single functional protein, that is what we refer to as the Quaternary protein structure. So it's when multiple amino acid chains come together. And so this year concludes our introduction to protein structure, and we'll be able to talk a little bit more about protein structure in our next lesson video, so I'll see you all there.

in this video, we're going to introduce denatured proteins and chaperones, and so it's important for you. All to note is that a protein structure and shape is actually really critical for its proper function. And so what this means is that a protein will not be able to properly function or properly work if it loses or changes its structure and shape. And so it's really the structure and shape that dictates the proteins function. And this idea leads us directly to the term de natured protein. And that is because a de natured protein is a protein that is non functional, a non functional protein that has altered its shape and so once again, by altering or changing the shape of a protein that will change its function and make it non functional. Now, denatured proteins can result from changes to the environment, and so examples of changes in the environment that could lead to a denatured protein include examples such as changes in the pH of the solution, Uh, changes in the temperature of the environment or changes in the salt concentration of the environment as well. All of these things can lead to the change of a protein's shape and therefore lead to a non functional protein, a denatured protein. Now, on the other hand, proteins that have lost their shape can sometimes regain their original shape by the help of what are known as chaperone proteins. And so chaperone proteins are proteins themselves that help other proteins reform their original shapes or re nature, if you will. And so let's take a look at our example image down below to get a better understanding of denatured proteins and chaperone proteins, and so what you'll need to notices over here on the left hand side. We're starting with a functional protein, which is this, uh, shape right here. This red structured and what's important to note is that it has a very, very specific shape. However, if the functional protein is, uh, heated, if the temperature changes in the environment, recall that the temperature is just one of the changes in the environment that can cause a functional protein to de nature and lose its shape. And so if we heat up the protein that can change the shape of the protein and so notice here, the protein has changed its shape in comparison to the functional form of the protein. And so what this means is, of course, we have a de natured protein here that has lost its shape and therefore lost its function. It will no longer work when it's Lou. When it's lost its shape, however, proteins can regain their shapes with the help of other proteins that we call chaperone proteins. And so the structure that you see here throughout is referring to the chaperone protein. And so the chaperone protein can take the denatured protein and basically help it reform its original structure. And so once the protein has regained its original shape and structure, it becomes a functional protein once again. And so chaperone proteins are good for cells. Toe have to make sure that they're proteins are properly folded. And so this year concludes our introduction to denatured proteins and chaperones, and we'll be able to get a little bit of practice applying these concepts as we move forward in our core. So I'll see you all in our next video