Ch1 Lipids

Question 1

4 Lipid characteristics

Answer 1

1. contain carbon, hydrogen and oxygen
2. proportion of oxygen: carbon+hydrogen is smaller than carbs
3. insoluble in water
4. soluble in organic solvents

Question 2

Roles of lipids

Answer 2

1. Cell membranes
2. Source of energy
3. Waterproofing
4. Insulation
5. Protection

Question 3

Source of energy

Answer 3

1. lipids provide over 2x more energy as carbs when oxidised
2. releases water

Question 4

Waterproofing

Answer 4

insoluble in water

Question 5

Insulation

Answer 5

1. slow conductor of heat
2. stored beneath body surface to retain body heat
3. electrical insulators in myelin sheath

Question 6

Triglyceride structure

Answer 6

1. three fatty acids + glycerol
2. ester bond
3. condensation reaction

Question 7

saturated

Answer 7

no carbon=carbon double bonds

Question 8

unsaturated

Answer 8

1. mono: 1C=C bond
2. poly- more than one C=C bond

Question 9

4 Trigylceride adaptations

Answer 9

1. high ratio of energy storing C-H bonds: C atoms for energy storage
2. low mass:energy ratio -lots energy in small volume
3. large, non-polar and insoluble- doesn’t affect water potential of cell
4. high H:O ratio so releases water when oxidised

Question 10

Phospholipid structure

Answer 10

2 fatty acids + glycerol + phosphate

Question 11

Phospholipid adaptations

Answer 11

1. Polar- bilayer in csm
2. hydrophilic phosphate head- hold surface of csm
3. can form glycolipids by bonding with carbs in csm
4. hydrophobic fatty acid tails- orients itself away from water

Question 12

Test for lipids

Answer 12

1. Add ethanol
2. Shake
3. Add water
4. Milky white-emulsion produced