In this video, we're going to talk about carbohydrate functions. And so it turns out that carbohydrates are structurally and functionally diverse, meaning that they can do so many different things for the cell because they can take on so many different types of structures. However, that being said, there are just two main functions that you all should be aware of when it comes to carbohydrate functions. The first function that you all should be aware of is structural support. Some carbohydrates are used specifically to build the structures of cells, and the structures either within cells or on the outside of cells.

For example, Cellulose and Chitin are two classic examples of some polysaccharides that are used for structural support. There are some others as well, for example, peptidoglycan might be one that you may or may not have heard of, but we're going to focus specifically on cellulose and chitin. Now the second primary main function that you should know that carbohydrates have is energy storage. Carbohydrates are specifically used for short-term energy storage, and they can provide energy to living cells. For example, starch and glycogen are both examples of carbohydrates that are used for short-term energy storage.

So let's take a look at our example down below to focus in on the polysaccharides that are in plants and animals and the functions that they have. Notice that we have this image down below of this grid where the first column we have the function, whether it is structural support like this Bob the Builder guy, or energy storage like these batteries over here. Then we have the polysaccharides that are found specifically in plants, here in this column, and the polysaccharides that are found specifically in animals over here in this column. Notice that we're showing you 2 structural support carbohydrates, 1 in plants and 1 in animals, and we're also showing you 2 energy storage carbohydrates, once again, 1 in plants and 1 in animals. It's a nice little grid here.

When we're talking about structural support, a classic example of a polysaccharide in plants that's used for structural support is cellulose. Cellulose is actually the most abundant carbohydrate that's found in plant cell walls, and when we take a look at plants like this leaf right here and we zoom in on its structure, what you'll notice is that the cell walls of these plants contain cellulose, and so it's used to build cell walls and that's why it is structural support. Now, a structural support carbohydrate in animals is going to be what we see over here, which is chitin. Chitin is a structural support carbohydrate that's found in the exoskeletons of insects and crustaceans such as lobsters. If we were to zoom into the exoskeleton shell here of this lobster, we would see that chitin would be found within its structure.

Chitin's structure is complex and we don't really need to worry about its particular structure so much, just knowing that chitin is an example of a structural support carbohydrate that's used to build the structures of exoskeletons. In terms of energy storage, we're showing you 2 as well over here in plants. Plants mainly store their energy in the form of starch. Starch is going to be the storage form of glucose specifically in plants, and you'll find lots and lots of starch inside of potatoes like this one over here. Over here what we have is an animal liver, and in animals, they store their energy in the form of glycogen.

Glycogen is a polysaccharide or carbohydrate whose main function is to store glucose in animal cells. This here concludes our introduction to carbohydrate functions and we'll be able to get some practice applying these concepts in our next few videos. So I'll see you all there.