1.5 Lipids

Question 1

What are lipids made of?

Answer 1

C, H & O

Question 2

Are lipids solluble?

Answer 2

No in water, yes in organic solvents

Question 3

What are the main groups of lipids?

Answer 3

Triglycerides & phospholipids

Question 4

What are the roles of lipids?

Answer 4

• Energy source
• Waterproofing
• Insulation
• Protection

Question 5

What are triglycerides?

Answer 5

Glycerol + 3 fatty acids -> 1 triglyceride + 3 water molecules

Question 6

What type of bond is formed between glycerol and 3 fatty acids

Answer 6

Ester bond

Question 7

What does saturated mean?

Answer 7

No double bonds between C atoms

Question 8

What does mono-saturated mean?

Answer 8

One double bond between C atoms

Question 9

What does poly-saturated mean?

Answer 9

More than one double bond between C atoms

Question 10

How do the structure of triglycerides relate to their properties?

Answer 10

• High ratio of C-H bonds; an excellent source of energy
• Low mass to energy ratio
• Large, non-polar, insoluble
• Releases water when oxidised

Question 11

What is the structure of a phospholipid?

Answer 11

A hydrophobic head & hydrophilic tail

Question 12

How do the structure of phospholipids relate to their properties?

Answer 12

-

Question 13

What is the test for lipids?

Answer 13

• 2cm of sample + 5cm of ethanol, shake
• 5cm of water, shake again
• lipid present = emulsion