UNIT ONE Biological Molecules - Lipids

Question 1

Describe the structure of triglycerides

Answer 1

Triglycerides are made up of one glycerol joined to three fatty acids

Question 2

Explain how triglycerides are formed

Answer 2

Glycerol has three ‘OH’ groups which each join to a fatty acid molecule during a condensation reaction where ester bonds are formed and 3H2O molecules are eliminated

Question 3

Define a saturated fatty acid

Answer 3

Saturated fatty acids don’t contain double bonds between carbon atoms in the hydrocarbon chain

Question 4

Define an unsaturated fatty acid

Answer 4

Unsaturated fatty acids do contain double bonds between carbon atoms in the hydrocarbon chain

Question 5

Describe the emulsion test

Answer 5

Add ethanol to sample and shake
Then add water and shake
A white emulsion forms if lipids are present

Question 6

Name the elements that make up lipids

Answer 6

Carbon
oxygen
hydrogen

Question 7

Name the 2 groups of lipids

Answer 7

triglycerides

phospholipids

Question 8

The formula for a fatty acid

Answer 8

RCOOH

Question 9

What are fatty acids made up of

Answer 9

A hydrocarbon chain and a carboxylic acid group

Question 10

In a fatty acid, what is the hydrocarbon chain referred to as ?

Answer 10

The R-group (it can vary in length)

Question 11

Describe the structure of a phospholipid

Answer 11

Phospholipids structurally consist of one glycerol attached to two fatty acid molecules and one phosphorus molecule