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Biochemistry

Learn the toughest concepts covered in Biochemistry with step-by-step video tutorials and practice problems by world-class tutors

1. Introduction to Biochemistry

Functional Groups

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Functional Groups & Linkages

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we're going to do a quick recap on functional groups. So you guys already know that functional groups are very specific portions of a molecule that are abundant and biomolecules and tend to be reactive. And in addition to that, they typically extend off of the carbon backbone of a molecule. And some functional groups can be further categorized as linkages because their specific arrangements of atoms that could be used toe link different kinds of molecules together. And so we'll be talking about functional groups and linkages throughout our entire biochemistry course. So it's important to be able to refresh and touch up on some of the common ones. And in our example below were going toe label, the functional groups and linkages. And so we'll start with the functional groups here that we have listed. And I wanna emphasize that the ending, why L or ill on a word is indicative that it is branching off of a chain and you'll see that throughout our patterns when we start toe label are functional groups. And so the first functional group that we have is the metal group, which, of course, you guys know it's simply a CH three group branching off of a carbon chain which is represented by our or the rest of the molecule. Now, our next functional group is, of course, one that you guys have seen plenty. And this is our hydroxyl group, which of course, is an oxygen atom bonded to a hydrogen atom. And so, uh, this is ah, hydroxyl group, and molecules that have hydroxyl groups are categorized as alcohol's. Now our next functional group is the soft hydro group, and you can see that the soft part here refers to the sulfur atom and the hide refers to the hydrogen atom. And so this is simply a software hydrogen atom branching off of a chain. And we'll see this when we talk about some of our proteins. Now the next functional group is a carbonnel group. This is a carbonnel group, which is simply a carbon atom double bonded to an oxygen atom. And we'll see this plenty of times incorporated into different functional groups. And on our next one, what you'll notice is that it indeed has a carbonnel group in it, but it also has a hydroxyl groups. Oh, when these atoms are arranged in this way, this makes a car box. Aled Group. Now, over here there's another functional group that you guys are very familiar with. And this is the amino group, which consists of just a nitrogen atom and hydrogen is, and we see those in proteins. And then our last functional group is the phosphate group, which, of course, has a phosphorus Adam in the center and its branching off of a chain, so that makes it a little bit easy to recognize. Now, down below, we have some linkages and notice that the linkages have our groups on either side of them. So that shows that they are able toe link different types of molecules together. And so we are. First linkage is our ether, and our next linkage is our Esther. So this is our Esther, so ethers and Esther's kind of sounds similar, and you might have been wondering why this creepy little freak over here has been staring at you guys this whole video. But pretty much what he's going to do is help us distinguish between the two. So ethers really do look like our friend over here, the ether bunny. So this is the Ether Bunny, and so notice that he's got those cute little buck teeth and whiskers sticking out. And he's also got these big floppy ears that looked just like the big floppy ears of our ether. And so, uh, the ether really does look like the ether bunny with these big floppy ears. And the Esther does not look so much like the ether bunny, and so that can help you hopefully distinguished between the two. Now notice that Esther's are very similar looking to car boxful groups. Now, car boxful groups are at the end of a molecule or noticed that the Esther is embedded within a molecule with the two are groups on the end. And then the next functional group that we have is our am I linkage, which we'll see in proteins when we talk about peptide bonds and so notice that this is also a derivative or spin off of the car boxful group. But it has a nitrogen Adam in there instead of the hydroxyl group. And so our next functional group is what's called our phosphor. Oh, our Foss fobo di Esther linkage. So this is a phosphor Oh, digester linkage. So notice that it has Foss photo indicating a phosphorus Adam and it has die in here indicating two of something. And then it also has Esther. So really, this is essentially an Esther and noticed that are esters have a double bonded here, and it has an oxygen here and notice that we have the same thing with our our group and our group over here. So you can see that this is essentially a Esther and that really, the only difference is that here we have Ah, carbon atom. And here we have a phosphorous atom. And so this is one phosphate ester linkage. But notice that on the other side we also have another phosphate ester linkage. So this makes a phosphor o di Esther linkage. And we'll see these when we talk about our nucleic acids in our next video. And then the last one that we have over here is a phosphor oh, and hydride linkage, which is represented by really this, uh to phosphate groups being connected together and also linking two different types of molecules. And so again, we'll talk about functional groups and linkages throughout our course. And this is a good summary. So I'll see you guys in our next video when we talk about functional groups and biomolecules
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Functional Groups in Biomolecules

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So as you guys already know, functional groups are common and biomolecules. And although the structures of biomolecules very greatly, there are consistent patterns in the functional groups and linkages, and they tend to appear frequently in specific types of molecules. So down below we have the four major macro molecules numbered, and the numbers correspond to the numbers and the example images below. So for the first one, you guys know that amino acids and proteins have amino groups as well as car boxful groups, and you can see that in the image below here for number one, where in amino acid has three amino group on one end, and the Car boxful group on the other now carbohydrates you guys know have plenty of hydroxyl groups, and because of that, they are Polly alcohols and they also tend tohave ether linkages so down below. In our example, you can see we have two different forms of the glucose molecule Ah, linear form and a cyclic form. And both forms have plenty of hydroxyl groups, which makes them Polly Alcohol's. And in addition to that, the cyclic form has an ether linkage shown by this oxygen, and the two ether bunny ears that air branching out to the our groups or the carbon atoms now lipids. They vary greatly in their structure, so it's a lot harder to find these consistent patterns and functional groups and languages. But that being said, a specific type of lipid known as the fatty acids typically have methyl groups so down below. What we'll see is that we have a specific type of lipid showing a foster lipid, and at the end of the hydrocarbon chains, we have these methyl groups being shown, and in addition to that, you can see that there are are other, uh, functional groups and linkages that we talked about previously. So you can see that we have ether linkage here linking the glycerol molecule to the two hydrocarbon chains, and we also have a phosphate group of above and a phosphate ester linkage that links the phosphate group to the glycerol molecule. Now, each nucleotide in a nucleic acid tends tohave phosphate, phosphate di ester linkages, phosphate die ester linkages and so you can see over here and our image for number four that we have two nucleotides linking together and they're linked by a phosphate di Esther linkage shown here. So you can see that there is one phosphate ester linkage shown in the highlighted region linking this phosphate group to this nuclear tied. And then on the other end, there's another phosphate ester linkage that links, uh, this nuclear tied to this phosphate groups. So this is a phosphate die, Esther linkage. And you can also see that there's an amino group on this, uh, on this nitrogenous space. And over here, you have an AM I'd linkage shown here, and so you can see that these functional groups appear frequently and we'll talk about them or as we move forward in our course. So this is a good summary, and I'll see you guys in the next video when we talk about what elements are essential to life.
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Essential Elements of Life

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So as you guys already know, the periodic table, which is shown below, contains all of the known elements of the universe. And of all of these known elements on Lee, a small subset of them is found in living organisms. And actually, what's quite amazing is that about 97% of the mass of most living organisms, which is a very large percentage here, consists of just six elements. And those six elements are carbon, hydrogen, nitrogen, oxygen, phosphorous and sulfur. And what helps me remember that is to remember chin ops. And so each of the letters here in China pops represents the first letter of each of these major elements, as well as the elements symbol in the periodic table below and notice that the synopsis color coded in a pinkish color to correspond with the pinkish color and the periodic table here. And so the other 3% of the mass of living organisms consists of 23 other elements that it can be grouped together as the trace elements, and the trace elements, of course, appear in very small amounts. But they can still have major biological roles, and they are actually important for life and are required for life. And these trace elements include the five essential ions of life, which are sodium chlorine, potassium, calcium and magnesium. So I would definitely remember the major elements of life. I would not memorize all of the 23 trace elements, but I would also remember the five essential ions. And so what helps me remember the essential ions is to think about for sodium and chlorine. I think about salts because sodium chloride makes up our salts. Bananas are a major source of potassium. Milk is a major source of calcium, and dark chocolate is a major source of magnesium. So when I think about salts, bananas, milk and chocolate, that helps me remember all of the essential ions. And so notice that the essential ions are color coded in dark purple to correspond with the dark purple that we see below in the periodic table. Now the light bluish color corresponds with the other trace elements, and again, the pinkish color corresponds with the major elements of life and the pinkish color in the periodic table. And so what you might notice is that there are some darker shades of blue here, and This is just representing the trace elements that tend to be mawr prevalent than other trace elements. So the darker ones arm or prevalent than the other trace elements. But I wouldn't worry about that so much in this video. And so this is a good summary of the elements of life, and I'll see you guys in our practice videos.
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Problem

Identify and label the functional groups and linkages in the following molecule:

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Problem

Which of the following elements likely make up the largest portion of the mass in an organism?

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