Cells

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Lipids

Lipids are biomolecules that includes fat, oil and steroids, and have a wide range of functions for life.

What do you normally think of when people say fats?

Fats are one of the three main biological molecules. We get these biological molecules from the food we eat. What do you think the other two biological molecules are?

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What other word do you think we use for fats in biology?

This shows the chemical structure of a lipid. How many different chemical elements does it contain?

What element do you think the $C$ stands for?

What element do you think the $H$ stands for?

What element do you think the $O$ stands for?

So lipids consist of 3 elements

Carbon $C$ , hydrogen $H$ and oxygen $O$ .

This example of a lipid consists of two parts.

Here those two parts are labelled A and B.

Three fatty acids are held together by a glycerol molecule. Which part is fatty acids? A or B?

So part B is fatty acids

That means part A is the glycerol molecule that holds them together.

There are different kinds of lipids. This one has three fatty acids, so what do you think we call this kind of lipid?

Triglycerides consist of a glycerol molecule and three fatty acids

Remember that "tri" means three. This is the kind of lipid we mainly find in body fat in humans for example.

There are different kinds of lipids. Apart from triglycerides, common examples include monoglycerides, diglycerides and phospholipids.

Try saying that with your mouth full! 🤣

A triglyceride contains...

True or false? Both the glycerol molecule and the fatty acids consist of carbon, hydrogen and oxygen.

True or false? Both the glycerol molecule and the fatty acids are chains of carbon atoms.

How many carbon atoms are in a glycerol molecule?

So both the glycerol molecule and the fatty acids are chains of carbon atoms.

A glycerol molecule has 3 carbon atoms. The number of carbon atoms in the fatty acid chains depends on what kind of fatty acid it is.

How many glycerol molecules does a lipid contain?

Triglycerides is a type of lipid. How many fatty acids does it contain?

Diglycerides is another type of lipid. How many fatty acids do you think they contain?

Pick all the options that are correct.

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To summarise! Lipids are fats

There are different kinds of lipids, for example monoglycerides, diglycerides, triglycerides and phospholipids.

Lipids contain 3 elements

Carbon $C$ , hydrogen $H$ and oxygen $O$ .

Triglycerides consist of two parts

One glycerol molecule that holds together three fatty acids.

The glycerol molecule and the fatty acids are all chains of carbon atoms

The glycerol molecule has 3 carbon atoms, but the number of carbon atoms in a fatty acid will depend on what kind of fatty acid it is.