Transcription
Okay, one of the things that you have to do in this unit is learn these functional groups, as they're called. Um, but you might be wondering, why isn't this a chemistry class? So why are you learning this? These are functional groups that we see a lot in biological molecules and carbs, in proteins, and fats. And learning these now will really, really help you in the future with feeling comfortable looking at diagrams of molecules, especially large biological molecules. And it'll help you in chemistry. And I've had students who've gone on to pharmacy programs tell me, "Oh my gosh, I'm so glad I learned the functional groups in bio181. It stuck with me for like years and years." So this is useful stuff.
Now, these functional groups, these are, um, collections of atoms that are joined together in specific ways, always the same way, always the same kind of layout. And they, um, cause a molecule to behave in a certain way or certain manner. So what this means is that if you know these functional groups and what they do or how they behave or the characteristics or the function that they give to a molecule, you, you might look at a molecule, you might have no idea what it is. You've never seen it before. It's a mystery molecule. But if you see an OH on it, just like, um, this one right here, there's an OH right here. Like if you see this OH on the molecule, you can say, "Oh, I know that. That's a hydroxyl group." And molecules that have hydroxyl groups behave in this specific kind of way. So even though you don't know exactly what the molecule is, you can make some predictions about how it's going to behave and what it's going to do chemically because it has a specific functional group on it. That's why these are so useful to know.
So there's a list here of about seven of them that are pretty common that you're going to see over and over. And what you need to do is to be able to learn the name. So we've got hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, and methyl. So those are our, um, main functional groups. Uh, you need to be able to know the name and spell the name. And they do look kind of funky, I get that. Um, and then you need to be able to draw them out. So you need to know what a hydroxyl group looks like. Or if you see a group, you need to say, "Oh, I can recognize that. That's a hydroxyl group." So you need to be able to go both ways with the information.
A couple of things, just a little sort of heads up. This is one of the few times where I do mark you down for bad spelling. And that's because of these two. They're very similar looking, carbonyl and carboxyl. So you need to be able to spell these separately. You will not get points for writing "carbon oxy." That doesn't exist. That's not a functional group. Seen it many times. It's either carbonyl or it's carboxyl. Make your mind up. You can't do both. All right, so that's number one.
The other thing that usually throws people is this R and a square. Like, what is that? If you look on the periodic table, there is nothing with the symbol R. Uh, so what could that possibly be? What this R stands for is basically the rest or the remainder of the molecule. So what this means is that there could be anything out here. It could have C, C, C, and then there's an OH. So this C, C, C is standing for this R. So instead of having to draw all these Cs, which are kind of boring and they don't tell us a whole lot, we just replace them with R and we say that's the remainder or the rest of it. That's kind of boring. But what's interesting is this molecule has a hydroxyl group sticking off the end. And hydroxyl groups can do certain things and they give molecules certain characteristics. And so that's why we kind of shorthand the rest of it because it's hard to draw some of these molecules out. They get big and complicated. We just shorthand it with an R and then we highlight what's the important bit, which in this case is the functional group.
So you can see this is a carbonyl, carboxyl. C double bond to an O, single bond to an O, and that's got an H on it. All right. So a couple other little things that, let's see, that catch people out. So a single OH is a hydroxyl. A C double bond O is a carbonyl. But if you have the C double bond O and the OH sticking onto the same carbon, so see they're both attached to this one carbon here, then you don't say this is two separate things. You don't do what I did here. I, I circled them separately. That's not correct. When they both stick on the same carbon, you circle the whole thing and say it's a carboxyl. So just an OH is a hydroxyl. Just a double bond O is a carbonyl. But when they're both sticking on the same carbon, then you call it a giant group altogether and you call it a carboxyl. You don't separate them out. And the amino, sulfhydryl, these ones are pretty easy to recognize. Then the methyl is this one down here.
Now, uh, in Canvas, in this table of extra information, uh, in the reading slides and videos page, there are a couple handouts. There's a handout like this to help you learn these. And there's also an additional handout that gives you a little bit more information about these functional groups. That you don't have to memorize that stuff. But I know for some people, a little bit more information and context makes it easier to remember things. So if you want some more details about these functional groups, you can find that there.