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.
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Meat contains useful fat for our diets, but too much can lead to heart disease.
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Fish is a very healthy source of oils in our diet.
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Nuts are a healthy source of oils.
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Butter is full of fat and we shouldn't eat too much. Butter is found in cakes and cookies.
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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.
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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.
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There are two patches where fat has been asborbed by the paper.
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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.
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The mixture on the right shows the presence of lipids.
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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.
Sources of Lipids
These foods contain a lot of fats and oils.
|
|
|
|
|
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.
|
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.
|
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