Open main menu

Lipid

Key Stage 3

Meaning

Lipids are molecules found in fats and oils.

About Lipids

Oil is better for us than fat, but we need some of both.
If we eat too much fat and oil then we can become obese.

Sources of Lipids

These foods contain a lot of fats and oils.
Meat.png
CookedFish.png
Nuts.png
Butter.png
CookingOil.png
Meat contains useful fat for our diets, but too much can lead to heart disease. Fish is a very healthy source of oils in our diet. Nuts are a healthy source of oils. Butter is full of fat and we shouldn't eat too much. Butter is found in cakes and cookies. Cooking oil is used to fry our food causing it to have a lot of oil inside it. A small amount is healthy but too much is bad for us.

Testing For Lipids

Adding lipids to paper can turn the paper translucent.
The Paper Test Method
1. Take a small sample of food.
2. Wipe it on a piece of paper.
3. Hold the paper up to the light.
4. If the paper has turned translucent the food contained lipids.
FatTest.png
There are two patches where fat has been asborbed by the paper.
The Alcohol Emulsion Test Method
1. Take a small sample of food.
2. Place the food in ethanol and mix by shaking or stirring.
3. Filter the mixture.
4. Add the clear solution to some water.
5. If lipids are present then a white emulsion will appear.
AlcoholEmulsionTest.png
The mixture on the right shows the presence of lipids.

Key Stage 4

Meaning

Lipids are molecules, made of a glycerol head and 3 fatty acid tails, that are found in fats and oils.

About Lipids

Lipids are an essential nutrient in our diet that is used in our nervous system.
Lipids store chemical energy at a higher energy density than carbohydrates so the body stores extra energy in fatty tissue made of lipids.
If there are too many lipids in our diet then we can become obese.
Lipids are broken down by our digestive system into glycerol and 3 fatty acids.
The fatty acids in lipids can be many different lengths but the glycerol head is the same for all lipids.
LipidDiagram.png
This diagram shows a simple representation of a lipid.

Sources of Lipids

These foods contain a lot of fats and oils.
Meat.png
CookedFish.png
Nuts.png
Butter.png
CookingOil.png
Meat contains useful fat for our diets, but too much can lead to heart disease. Fish is a very healthy source of oils in our diet. Nuts are a healthy source of oils. Butter is full of fat and we shouldn't eat too much. Butter is found in cakes and cookies. Cooking oil is used to fry our food causing it to have a lot of oil inside it. A small amount is healthy but too much is bad for us.

Testing For Lipids

Adding lipids to paper can turn the paper translucent.
The Paper Test Method
1. Take a small sample of food.
2. Wipe it on a piece of paper.
3. Hold the paper up to the light.
4. If the paper has turned translucent the food contained lipids.
FatTest.png
There are two patches where fat has been asborbed by the paper.
The Alcohol Emulsion Test Method
1. Take a small sample of food.
2. Place the food in ethanol and mix by shaking or stirring.
3. Filter the mixture.
4. Add the clear solution to some water.
5. If lipids are present then a white emulsion will appear.
AlcoholEmulsionTest.png
The mixture on the right shows the presence of lipids.

References

AQA

Lipids (test for), page 28, GCSE Combined Science; The Revision Guide, CGP, AQA
Lipids (test for), page 32, GCSE Biology; The Revision Guide, CGP, AQA
Lipids, pages 40-41, 129, 162-163, GCSE Biology; Third Edition, Oxford University Press, AQA
Lipids, test for, page 48, GCSE Combined Science Trilogy 1, Hodder, AQA
Fat, page 101, 103, GCSE Biology; Student Book, Collins, AQA

Edexcel

Lipids, page 124, GCSE Biology, Pearson, Edexcel
Lipids, page 17, GCSE Combined Science; The Revision Guide, CGP, Edexcel
Lipids, page 86, GCSE Combined Science, Pearson Edexcel
Lipids, pages 18, 19, GCSE Biology; The Revision Guide, CGP, Edexcel
Lipids, pages 42, 45, GCSE Biology, CGP, Edexcel

OCR

Fats, pages 39, 66, 252, Gateway GCSE Biology, Oxford, OCR
Lipids, page 20, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Lipids, page 23, Gateway GCSE Biology; The Revision Guide, CGP, OCR
Lipids, pages 39, 252, Gateway GCSE Biology, Oxford, OCR
Lipids; testing for, page 24, Gateway GCSE Biology; The Revision Guide, CGP, OCR

Beyond the Curriculum