Lipids

Question 1

Features of triglycerides

Answer 1

-non polar
-hydrophobic
-made up of one glycerol and three fatty acids

Question 2

How do fatty acids vary?

Answer 2

-length of hydrocarbon chain (R group)
-fatty acid chain may be saturated or unsaturated

Question 3

Where are saturated and unsaturated lipids found?

Answer 3

• animal fats: saturated don’t have c=c,
• plant fats: unsaturated have c=c bonds, so molecule can bend and cannot pack tightly together so are liquid at room temperature

Question 4

how is their structure related to their properties?

Answer 4

high ration of energy storing carbon-hydrogen bonds:carbon atoms means they are an excellent energy store
-low mass:energy meaning that they are a good storage molecule, lot of energy in small volume
-large and non-polar so insoluble in water therefore storage not affected by water potential in cells
-release water when they are oxidised because of high ratio of hydrogen-oxygen atoms

Question 5

what is the structure if a phospholipid?

Answer 5

one glycerol, two fatty acids and one phosphate-containing group

Question 6

what are the features of a phospholipid?

Answer 6

-phosphate heads are hydrophilic
-tails are hydrophobic
- as a result phospholipids form micelles when in contact with water
-molecule is polar

Question 7

how is a phospholipid structure related to their properties?

Answer 7

-polar means a bilateral can be formed
-can form glycolipids with carbohydrates which are important for cell recognition

Question 8

How to carry out emulsion test

Answer 8

-use a grease free test tube and add sample
-add ethanol and shake to dissolve all lipid in solution
-add distilled water and shake
-positive test will form a cloudy-white solution