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Video transcript

what we're going to do in this video is talk about proteins and some of you all might already be familiar with them at least in some context if you look at any type of packaging on food you'll oftentimes see a label that has protein listed and a certain number of grams per serving and some of you who might be athletically inclined might associate it with things that help you build muscle and none of that is incorrect but as we'll see in this video and in many future videos proteins are involved in almost every single biological process in every single living organism and if we ask ourselves what are they well they're biomolecules they're molecules found in biological systems and they're large biomolecules we could call them macro molecules molecules which is just referring to they're made up of many many many many many atoms these right here are pictures two different views of the chaperonin protein and this is the chaperonin protein is roughly 800,000 times the mass of a hydrogen atom so it's going to contain tens of thousands of atoms which would very much make it a macro molecule now one thing to be careful of even though these are very very large on a molecular scale even the largest protein we know of titan is about 1 micrometer in length and that's much larger than this sapper Onan here and a micrometer is one thousandth of a millimetre so even the largest proteins are microscopic now another way to think about proteins is what they are made up of so some proteins are made up of a single chain of something called amino acids and things like chaperonin are made up of multiple chains of amino acids so in a little bit I'll show you some particular amino acids but for now just think of them as the building blocks of proteins so let's say that's an amino acid and then it will bond to another amino acid it's not just one type of amino acid and they can form these really really really long chains and so let me be very clear this is an amino acid and it's called that because it contains an amine group which you have to worry about for now and they are the monomers that form the polymers of what's known as polypeptide chains so these are monomers you built you connect them together and and you could keep going you can have hundreds or even thousands of these and so this whole thing right over here you can consider to be a polymer and a chain of amino acids the polymer of amino acids is known as a polypeptide poly peptide and sometimes a polypeptide chain is a protein but sometimes a protein can be made up of multiple polypeptide chains put together and what happens is after these amino acids connect or bond to each other there they they Bend and they form the shape of these proteins so you can imagine the chaperone in protein right over here it has these chains of amino acids that Bend have a conformation that form this shape and that's really what gives proteins their power and as I mentioned proteins are involved in almost every single biological function they play a structural structural role they play a mechanical role when your muscles contract you have actin and myosin proteins interacting with each other so that your muscle contracts they can act as enzymes which we will talk about in a lot more depth in future videos enzymes help catalyze reactions they help biological biochemical reactions happen in biological systems they can be involved with the immune system they could be involved with signaling they can send signals from one part of the body to another or they can be receptors on cells that receive signals so proteins are incredibly incredibly important now with that out of the way let's dig a little bit deeper into the building blocks of proteins the monomers that build up the polymers that are polypeptides which could be proteins or which could be used to build up proteins so what we see on the left here is the typical structure of an amino acid notice you see some oxygens you see some hydrogen's some carbons and nitrogen and then bonded to this carbon right over here you see this R and you say what element is that well this is not an element this is referring this is kind of a placeholder for a side chain which differentiates the common amino acids and you see some of the common amino acids in this diagram right over here and you can see what the R would be for this arginine right over here that our group would be this part and you don't have to understand the biochemistry of it in too much detail but you can see that they all have this top part in common but then they all have a different R group right over here and it's different sequences of these amino acids that give us the diversity of all of the proteins that we have in biological systems and all of the very shapes and it really really really really is amazing I mean just going back to this picture of chaperonin which is involved with helping other proteins get their shape there its chaperones the protein folding process so to speak just think about the complexity this looks like a complex machine but it forms naturally in biological systems and as we explore more and more biology we keep seeing these fascinating proteins that look like these incredible systems that really boggle the imagination
Biology is brought to you with support from the Amgen Foundation