Lipids

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What is a lipid?
A fatty acid
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Why do lipids not mix with water?
Because they are non-polar molecules
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What is the name given to large complex molecules with large molecular weight?
Macromolecules (lipids are macromolecules)
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Describe a saturated lipid
A lipid with only single bonds and all of the carbons have their maximum number of bonds
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Describe a mono-unsaturated lipid
A lipid with ONE double bond
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Describe a poly-unsaturated lipid
A lipid with 2 or more double bonds
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Name a characteristic of unsaturated lipids
The double bonds give the chain a kink, the more double bonds, the more compact they are. Thus why unsaturated lipids tend to be liquid.
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What is the name of the bonds in lipids?
Ester bonds
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What is the structure of a triglyceride?
A glycerol molecule (alcohol group) and 3 fatty acids (carboxylic acid group)
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How are triglycerides formed?
Esterfication (a type of hydrolysis)- The hydroxyl groups from both the glycerol molecule and the fatty acids interact, 3 waters are then given off
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How do you break down a triglyceride?
Add 3 waters to 1 triglyceride molecule
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How is a phospholipid a "modified triglyceride"?
One of the fatty acids in the triglyceride is replaced with a phosphate
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Describe how phospholipids interact with water and why
Forms a layer on water due to the hydrophilic heads (polar) and their hydrophobic tails (non-polar), the tails stick out of the water and the head go in the water, making them surface active agents
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What is a sterol?
A steroid alcohol
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Describe the structure of a sterol
4 carbon ring structure (non-polar, hyrdophobic) with a hydroxyl group (polar, hydrophylic) on the end
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Give an example of a sterol
Cholesterol
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What are the roles of lipids?
Waterproofing, long term energy store, buoyancy for aquatic animals, insulation, protection of vital organs, membrane formation, hormone production
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What is the test for lipids?
Emulsion test- Mix sample with ethanol, mix with water
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Positive result for lipid
Turns cloudy/ milky because a white emulsion forms
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Other cards in this set

Card 2

Front

Why do lipids not mix with water?

Back

Because they are non-polar molecules

Card 3

Front

What is the name given to large complex molecules with large molecular weight?

Back

Preview of the front of card 3

Card 4

Front

Describe a saturated lipid

Back

Preview of the front of card 4

Card 5

Front

Describe a mono-unsaturated lipid

Back

Preview of the front of card 5
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