Iipids

Question 1

What are the components of a triglyceride?

Answer 1

One glycerol and three fatty acids with long tails of hydrocarbons

Question 2

Are the fatty acid tails hydrophilic or hydrophobic

Answer 2

Hydrophobic makes them insoluble

Question 3

What is the structure of a saturated fatty acid?

Answer 3

Saturated fatty acids don’t have any double bonds between their carbon atoms. The fatty acid is saturated with hydrogen

Question 4

What is the structure of an unsaturated fatty acid?

Answer 4

Unsaturated fatty acids do have double bonds between carbon atoms, which makes the chain kink

Question 5

Give two reasons why triglycerides are used as energy storage molecules

Answer 5

Because they contain lots of chemical energy and they’re insoluble in water

Question 6

Explain how the structure of phospholipids make them able to form the bilayer of cell membranes

Answer 6

Phospholipid heads are hydrophilic and their tails are hydrophobic, so they form a double layer with their heads facing out towards the water on either side. This makes the centre of the membrane bilayer hydrophobic, so water soluble substances can’t easily pass through it.

Question 7

What is the emulsion test used to test for?

Answer 7

Fats, oils, lipids

Question 8

Describe how the student should carry out the test? (Emulsion)

Answer 8

The student should shake the test substance with ethanol for about a minute, before pouring the solution into water. A milky emulsion will appear if the result is positive.

Question 9

What are the components of a phospholipid?

Answer 9

Phosphate group, glycerol, ester bond, fatty acid/hydrocarbon tail