Lipids

Question 1

What elements are they made up off?

Answer 1

Nitrogen, oxygen, hydrogen

Question 2

Why are lipids insoluble in water?

Answer 2

They are hydrophobic and are non-polar

Question 3

Why are lipids used in energy storage usually rather than carbohydrates?

Answer 3

They have a higher yield of energy per gram than carbohydrates

Question 4

State some functions of lipids

Answer 4

-Used for energy (give more than glucose) and storage in adipose cells in fat store
-Protecc gentle organs e.g. kidneys
-Makes up membranes in plants+animals
-Bad conductors of heat, can retain body heat
-Waterproofing as waxy cubicle in plants/insects
-Cholesterol, sits between hydrocarbon tails, regulate fluidity of membrane

Question 5

What are triglycerides made up of and what is their structure? What is the bond formed in condensation?

Answer 5

-Glycerol and 3 fatty acids
-Ester bond
-Long molecules with hydrophilic end and hydrophobic tail

Question 6

Draw a triglyceride, bonded and hydrolysis

Question 7

What are saturated fatty acids and what is their structure?

Answer 7

-Found in animals
-Carbon bonded by single bonds
-Hydrocarbon chain which is straight
-High melting point

Question 8

What are unsaturated fatty acids and what is their structure?

Answer 8

-Found in plants
-Can have one double C=C bond or multiple (poly-unsaturated)
-Bent chains
-Low melting point

Question 9

What structure does a phosphatide (phospholipid) have?

Answer 9

-Glycerol, 2 fatty acids and phosphate group
-Hydrophilic head that points towards water
-Hydrophobic tail that points away from h2o

Question 10

What does a phosphatide and water make? What could it form?

Answer 10

-Micelle, a sphere with hydrophobic tail hydrophilic head
-Phosphide bilayer (liposome), water trapped middle

Question 11

What are lipoproteins?

Answer 11

-Protein and lipid in blood plasma

Question 12

What are low density lipoproteins?

Answer 12

-Transport cholesterol from cells to blood
-More saturated fat, more release from liver
-Fat delivered too cells in arteries, where blockage can happen, atheroma

Question 13

What are high density lipoproteins?

Answer 13

-Scavenge for LDL and take them back to the liver
-More unsaturated fat, more release from liver and reduced change of heart related diseases, as less fat can block arteries

Question 14

What bond is made between a glycerol and fatty acid?

Answer 14

Ester bond

Question 15

How thick is the phospholipid bilayer?

Answer 15

Approx. 7.5nm thick