Lipids

Question 1

How are triglycerides formed

Answer 1

1. One glycerol and three fatty acids;
2. Condensation(reactions) and removal
   of three molecules of water;
3. Ester bond(s) (formed);

Question 2

Phospholipids compared with
Triglycerides (8)

Answer 2

1. Both contain ester bonds (between glycerol and fatty acid);
2. Both contain glycerol;
3. Fatty acids on both may be saturated or unsaturated;
4. Both are insoluble in water;
5. Both contain C, H and O but phospholipids also contain P;
6. Triglyceride has three fatty acids and phospholipid has two fatty acids plus phosphate group;
7. Triglycerides are hydrophobic/non-polar and phospholipids have hydrophilic/polar and hydrophobic/polar region;
8. Phospholipids form monolayer (on surface)/micelle/bilayer (in water) but
   triglycerides don’t;

Question 3

Describe how an ester bond is formed in a
phospholipid molecule.

Answer 3

1. Condensation reaction
2. Between glycerol and fatty acid

Question 4

Test for a lipid

Answer 4

1. (Mix / shake sample) with ethanol,
   then water;
   Sequence is important
2. White / milky (emulsion);