Lipids (B) Flashcards

Triglycerides and phospholipids

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1
Q

Describe the structure of a triglyceride molecule

A

3 fatty acids joined to 1 glycerol molecule

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2
Q

In the condensation reaction between a glycerol molecule and a fatty acid what bond is formed?

A

An ester bond

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2
Q

Describe the formation of a triglyceride

A

They are joined in 3 separate condensation reactions with the loss of three water molecules

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3
Q

How many ester bonds are in a triglyceride molecule

A

3 ester bonds

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3
Q

Glycerol + 3 fatty acids →

A

Triglyceride + 3 water

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4
Q

What are the properties of triglycerides

A

Cows Have No Worries
C: Contain many carbon-hydrogen bonds, releasing twice the energy of carbohydrates during aerobic respiration.
H: High hydrogen-to-oxygen ratio, releasing water during respiration, this is vital for desert organisms
N: Non-polar and insoluble in water, making them ideal for energy storage as they are osmotically inactive
W: Presence in the waxy cuticle of insects and plant leaves where their insolubility helps to reduce water loss

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5
Q

What are phospholipids?

A

Lipids containing a phosphate group

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6
Q

What molecules are phospholipids made up of?

A

One glycerol molecule, two fatty acid molecules and one phosphate group

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6
Q

What bonds does the condensation reaction form?

A

Ester bonds

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7
Q

What is unique about phospholipid molecules?

A

They have a polar hydrophilic head containing the phosphate group and a non polar hydrophobic tail consisting of the long fatty acid chains

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8
Q

What does hydrophilic mean?
What does hydrophobic mean?

A

Attracting water
Repelling water

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9
Q

Where are bilayers formed?

A

In cell membranes

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9
Q

What are the two types of layers that phospholipids can form?

A

Monolayers and bilayers

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10
Q

Both triglycerides and phospholipids are:

A

Insoluble in water
Contain glycerol
Contain ester bonds
Contain carbon, hydrogen and oxygen

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11
Q

Differences between triglycerides and phospholipids

A

Triglycerides have 3 fatty acids while phospholipids have 2 fatty acids plus a phosphate group
Triglycerides are hydrophobic (non polar) while phospholipids have hydrophilic and hydrophobic regions

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12
Q

What is the emulsion test for lipids

A

A small amount of the sample is placed into a test tube with ethanol
Shake the mixture so the fat dissolves
Add this to water in another test tube and mix the contents
A white emulsion indicates lipid is present