In this video, we're going to begin our lesson on sphingoglycolipids. Now first, let's take a look at our lipid map to make sure everyone's on the same page. And of course, we know that currently we're exploring the fatty acid-based lipids. And already in our previous lesson videos, we've already explored the glycerolipids, and we're currently starting to explore the sphingolipids. So, we already talked about sphingophospholipids and sphingomyelin. And so now in this video, we're going to talk about sphingoglycolipids. And so sphingoglycolipids, as the name implies, are just sphingolipids covalently attached to a carbohydrate group or a sugar group for that matter. And so glyco, you might recall from our carbohydrate videos, just means or indicates carbohydrates or sugars. Now be careful not to confuse the prefix glyco with the prefix glycero. Recall that glycero is referring to a glycerol molecule, a 3-carbon glycerol molecule. Whereas glyco is referring to a carbohydrate that could have a lot more than just 3 carbons. And so again, be careful not to confuse these two here. Now, moving forward, we're going to talk about different types of sphingoglycolipids. And in our next lesson video, we're going to introduce cerebrosides and globosides, and then a little later we'll introduce the gangliosides. And these are all falling under the category of glycolipids because these are lipids that are attached to sugars, the glyco prefix once again. Join us in our next video to talk further about these in more detail.
Sphingoglycolipids - Video Tutorials & Practice Problems
Sphingoglycolipids
Video transcript
Sphingoglycolipids
Video transcript
In this video, we're going to introduce cerebrosides and globosides. And so cerebrosides are just a specific type of sphingoglycolipid. And, of course, the glyco prefix we know from our last lesson video just means that it contains a carbohydrate or a sugar unit. But more specifically, cerebrosides are going to contain only one single sugar residue as the head group. Now typically, cerebrosides are going to be found in membranes of nerve and brain tissues and that's why it has the prefix cerebro because the prefix cerebro means head and it makes sense that they're going to be found in our heads or in our brains. And so if we take a look down below at our image, notice what we've got here is the base of a sphingolipid. And as the variable head group, what we have is a sugar unit. And this, if it's a single sugar residue or a single sugar unit, then it's going to be considered a cerebroside. And notice that this sugar unit can actually be different sugars. It could be a glucose molecule, like this one right here, or it could be a galactose molecule like this one over here. And both of these are cerebrosides because again, they only have one sugar unit and again, they're going to be found in our heads or in our brain membranes. Now, globosides on the other hand, these are also sphingoglycolipids, but they contain more than just a single sugar residue. These contain greater than or equal to 2 sugar residues. So they have more than one sugar residue as the head group. And so if we wanted to get a globoside, all we would really need to do is attach another sugar unit right here and there you go. You've got yourself a globoside. So pretty easy idea, just greater than 2 sugar units. And so this here concludes our introduction to cerebrosides and globosides, and in our next lesson video, we're going to introduce gangliosides. So I'll see you guys there.
Sphingoglycolipids
Video transcript
In this video, we're going to introduce gangliosides. Gangliosides are yet another type of sphingoglycolipid. The 'glyco' here tells us that it's going to contain some type of carbohydrate or sugar unit. But more specifically, these gangliosides are going to contain a complex and branched oligosaccharide as the head group. These complex and branched oligosaccharides are going to contain at least 1 sialic acid residue, which is really just a sugar acid derivative and aldonic acid if you might recall from our previous lesson videos. The most common sialic acid residue found in these gangliosides are N-acetylneuraminic acid residues or Neu5Ac for short. Notice that it is containing the same sphingolipid base here and branching off as the variable head group, what we have is a complex oligosaccharide. You can see that we have these different sugar units here and it is a branched oligosaccharide as well and it contains this sialic acid residue, which is again, N-acetylneuraminic acid or Neu5Ac. What's really important to note about these gangliosides is that defects in the ganglioside metabolism can actually lead to many different diseases, including a disease known as Tay-Sachs disease, which is a neurodegenerative disease that has many different symptoms including blindness and can actually lead to death as well. Below, what we have is this image here just to remind you that defects in ganglioside metabolism can lead to Tay-Sachs. So, the most important thing is to associate that these gangliosides are important because otherwise, if they're not metabolized correctly, it could lead to diseases. This concludes our introduction to gangliosides, and we'll be able to get some practice applying the concepts that we've learned here in our next few videos. So I'll see you guys there.
Sphingosine is not a component of:
A) Sphingomyelin.
B) Ceramide.
C) Cerebrosides.
D) Gangliosides.
E) Phosphatidylcholine.
Tay-Sachs disease is caused by an inability to degrade:
A.) Sphingosine.
B) Gangliosides.
C) Ceramide.
D) Dipalmitoyl phosphatidyl choline.
E) Carbohydrates.
Which of the following is true regarding a ganglioside?
A) It has 3 hydrocarbon tails.
B) It is the most abundant membrane lipid molecule.
C) It is a sterol lipid.
D) It contains oligosaccharides with one or more sialic acid residues.
E) It is found in myelin sheath cells.
