Lipids

Question 1

Name the elements that lipids are composed of

Answer 1

C,H and O

Question 2

Describe lipids

Answer 2

• Have a low proportion of O to C and H than carbohydrates
• are insoluble in water
• soluble in organic substances

Question 3

Describe the functions of lipids

Answer 3

• Important energy storage molecule
• Used for waterproofing
• Used for insulation

Question 4

Describe the states of fats + oils in 10-20 degrees temp.

Answer 4

Fats - solid

Oils - liquid

Question 5

State what makes up triglycerides (draw a diagram)

Answer 5

3 hydrocarbon tails (fatty acids)
a glycerol unit
(forms an ester bond - condensation reaction)

Question 6

Describe the make up of triglycerides

Answer 6

• High ratio of energy storing C-H bonds
• Large + insoluble
• low energy to mass ratio
• High ratio of H to O + release H2O when oxidised

Question 7

Describe triglycerides

Answer 7

• High ratio of energy storing C-H bonds
• Large + insoluble
• low energy to mass ratio
• High ratio of H to O + release H2O when oxidised

Question 8

Describe the structure of phospholipids (draw a diagram)

Answer 8

similar to triglycerides except 1 fatty acid is replaced with a phosphate molecule (phosphate can have more things attached)

Question 9

Describe phospholipids

Answer 9

hydrophilic head + hydrophobic tails (also are polar)

Question 10

What is the difference between a saturated and unsaturated fat?

Answer 10

unsaturated: bent with double bonds (more fluid)
saturated: straight with single bonds (more viscous)

Question 11

What is the test for lipids?

Answer 11

The emulsion test - add ethanol + gently shake. White emulsion formed