Fatty acid molecules have 'long tails'- what are they made of?
Hydrocarbons
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What type of reaction occurs to join fatty acids to a glycerol molecule?
A condensation reaction
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What bond is formed between the glycerol molecule and the fatty acids?
An ester bond
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What molecule is released for every fatty acid that joins onto a glycerol molecule?
A water molecule
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Draw a diagram of a condensation reaction for the formation of a triglyceride
Page 6 of revision guide
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How can you tell that a fatty acid is saturated or unsaturated?
If it is unstaurated there will be one or more double bonds between carbon atoms in the hydrocarbon tails (R group)
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Where are phosholipids found?
Cell membranes
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How does a phospholipid differ from a triglyceride?
It has a phosphate group instead of one of the fatty acids
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Is the phosphate group hydrophilic or hydrophobic?
Hydrophilic
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Are they fatty acid tails hydrophilic or hydrophobic?
Hydrophobic
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What function does a triglyceride have?
It is used as an energy storage molecule
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Give two ways in which a triglyceride is suited to its function
- Long hydrocarbon tails of the fatty acids contain lots of chemical energy so a lot of energy is released when they are broken down - They're insoluble so they don't affcet the water potential of a cell (don't allow osmosis)
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Draw the structure of a group of triglyceride molecules
Page 7 of revision guide
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What is the structure of several triglyceride molecules like? Why?
They clump together and form into droplets because the fatty acid tails are hydrophobic and all face inwards shielding themselves form the water with their glycerol heads
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What is the function of a phospholipid?
They make up the bilayer of cell membranes (that control what goes in and out of the cell)
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Draw the structure of a group of phospholipid molecules
Page 7 of revision guide
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Explain how phospholipids are suited to their function
The centre of the bilayer is hydrophobic, so doesn't let water-soluble substances in easily, acting as a barrier
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What method would be used to carry out the test for lipids?
- Add ethanol to a sample in a test tube - shake for about a minute to let it dissolve - pour the solution into water
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What is a positive result for the test for lipds?
Milky white emulsion
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What is the test for lipids also known as?
The emulsion test
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Other cards in this set
Card 2
Front
Fatty acid molecules have 'long tails'- what are they made of?
Back
Hydrocarbons
Card 3
Front
What type of reaction occurs to join fatty acids to a glycerol molecule?
Back
Card 4
Front
What bond is formed between the glycerol molecule and the fatty acids?
Back
Card 5
Front
What molecule is released for every fatty acid that joins onto a glycerol molecule?
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