There are probably many images that come to mind when you hear the word ‘fat.
‘ This lesson is all about fat and will explore the structure and function of this often misunderstood lipid.
Definition of Fats
Chances are, you are familiar with fats. Maybe you’ve read the nutritional labels for foods and try to avoid eating too much fat, or maybe you’ve shivered in the cold and thought, ‘I need some extra fat to stay warm!’ When you hear the word ‘fat’, different images probably come to mind, like a big gob of goo or a chunk of meat dripping with oils.
But fats are much more complicated than gobs of goo that you try to avoid.Fats are large molecules that are classified as lipids and are made up of glycerol and fatty acids. What do those vocabulary words mean, exactly? Let’s go through them next, while we also go over the structure of fasts.
We’ll also learn about the functions of fats, including energy storage and body insulation.
The Structure of Fats
Fats are classified as lipids, or a group of compounds which are substances made up of two or more elements that do not dissolve in water. For example, what happens when you place olive oil in water? It floats on top because it does not dissolve. Olive oil is classified as a lipid.Glycerol is part of the structure of fat and is made up of three carbon atoms.
Each carbon atom can bond, or attach, to four other atoms. One of those bonds is made with a hydroxyl-group, or a hydrogen and oxygen. The other three bonds are with carbon and hydrogen atoms.
Take a look at the image below to get a better idea. Note: O stands for oxygen, H stands for hydrogen, and C stands for carbon.
Saturated and Unsaturated Fats
There are two main types of triglycerides: saturated fats and unsaturated fats.
Unsaturated fats have at least one double bond in the long carbon chain, whereas saturated fats do not have at least one double bond. Most animal fats, like bacon grease and butter, are saturated fats and are solids at room temperature. Unsaturated fats are typically liquid at room temperature and consist of oils.Take a closer look at the image below.
In this image, the fatty acid has not joined up with a glycerol yet to form a fat. Notice there are no double bonds. Also note the carboxyl-group is outlined in red.
The Function of Fat
Fats are found in foods and are extremely important for our health, even though you might often think of fats as bad.
Let’s now look at some important functions of fat:
- It provides energy. After your body uses up carbohydrates (breads, for example) it starts using fats.
- It helps absorb vitamins. Some vitamins will only be absorbed in the presence of fats. These include vitamins A, D, E, and K.
- Sometimes you eat more than you need, and the excess is stored as fat for future use.
- Fat helps cushion organs.
- There is a thin layer of fat beneath your skin, which helps to insulate you and maintain your body temperature.
- Fats make up the membranes, or outer coverings, of our cells.
- Fats are ingredients for mylelin.
Mylelin is an outer covering for nerves that helps speed up nerve transmission.
- Fats are involved in making hormones.
Although they often get a bad rap, fats are important! Fats are large molecules that are classified as lipids and are made up of glycerol and fatty acids.
Lipids are compounds that don’t dissolve in water. In terms of numbers, fat is made up of one gylcerol, which is part of the structure of fat and is made up of three carbon atoms, and three fatty acids, which have a long chain of carbons. Glycerol can be distinguished by its hydroxyl-group, whereas fatty acids can be distinguished by their long carbon chains and carboxyl-groups. There are two main types of fat: saturated and unsaturated. Unsaturated fats have double bonds in the carbon chain, while saturated fats don’t have double bonds in the carbon chain.Fats serve several different purposes: from being an ingredient in our cell membranes to cushioning our organs to being stored for future use in energy to even coating our neurons with myelin, which is an outer covering for nerves that helps speed up nerve transmission.