Lipids

Question 1

What’s a lipid?

Answer 1

Fat

Question 2

What are 8 uses of lipids in biological molecules?

Answer 2

Water proofing
Insulation
Protection of organs
Membrane structure
Energy
Hormones
Buoyancy
Source of water

Question 3

What do triglycerides contain?

Answer 3

Glycerol and 3 fatty acids by condensation reaction

Question 4

Is glycerol hydrophilic or hydrophobic?

Answer 4

Hydrophilic - can attract water as its charged

Question 5

Are fatty acids hydrophilic or hydrophobic?

Answer 5

Hydrophobic - not charged so repels water

Question 6

How many water molecules are lost in the formation of a triglyceride?

Answer 6

3

Question 7

What is the bond that forms between fatty acids and the glycerol molecule?

Answer 7

Ester band

Question 8

What is the functional group called on a fatty acid?

Answer 8

Carboxylic / carboxyl group

Question 9

What does R group mean?

Answer 9

Fatty acids

Question 10

What does a saturated fat contain?

Answer 10

Hydrocarbon chain has only single bonds between carbons
Can be layered

Question 11

Where does an unsaturated fat contain?

Answer 11

Hydrocarbon chain consists of at least one double bond between carbons
Can’t be layered

Question 12

What is an unsaturated fat as room temp?

Answer 12

Liquid

Question 13

Name 4 properties of triglycerides?

Answer 13

Energy storage- many c h bonds
Low mass - lots of energy stored in small space
Large non polar molecules so insoluble
Source of water - release water it oxidised

Question 14

What is the food test for lipids?

Answer 14

Emulsion test

Question 15

Describe emulsion test

Answer 15

• Dissolve the sample in ethanol
• add distilled water and shake
• positive, white emission forms

Question 16

What’s In a phospholipid?

Answer 16

Glycerol molecule, 2 fatty acids and 1 phosphate group

Question 17

What cellular structure contains phospholipids?

Answer 17

Cell membrane - phospholipid bilayer