Lipids

Question 1

What are the main uses of lipids ?

Answer 1

Lipids are used in the neurone is to increase rate of reactions in the myelin sheath.
Waterproofing in the waxy cuticle of leaves.

Question 2

How is a triglyceride formed ?

Answer 2

Formed by a condensation reaction.
The hydroxide from the glycerol and the hydrogen from a fatty acid bond to create water which is then expelled.
As Ester bond replaces the water. Jks happens three times therefore meaning that 3 water molecules are formed during production of a triglyceride.

Question 3

How many water molecules are made during the production a triglyceride.

Answer 3

3

Question 4

Draw the structure of glycerol.

Answer 4

X

Question 5

What components are in a fatty acid.

Answer 5

Carbonyl group and fatty acid tail.

Question 6

What does r mean on a fatty acid.

Answer 6

Variable reaching in the structure of a fatty acid.

Question 7

What is a saturated fatty acids.

Answer 7

All single carbon bonds.

Question 8

What are unsaturated fatty acids.

Answer 8

Double carbon bonds.

Question 9

What does monounsaturated mean ?

Answer 9

1 double carbon bond in the chain.

Question 10

What does polyunsaturated mean ?

Answer 10

More than one double carbon bond in a chain.

Question 11

What does ‘Cis’ isomeration mean ?

Answer 11

Both hydrogen’s are on the same side of the chain.

Attached to the double bond.

Question 12

What is trans isomerism ?

Draw a diagram to explain

Answer 12

Hydrogen’s are on different sides of the double carbon bond.

Question 13

What are the characteristics of lipids ?

Answer 13

They are non soluble and not considered polymers as long lipid chains cannot be formed.

Question 14

Define fatty acid.

Answer 14

Fatty acid hydroxide tail and a carboxyl group.

Question 15

Define saturated fatty acids.

Answer 15

All single carbon to carbon bonds.

Question 16

Give examples of lipids.

Answer 16

Phospholipids and Triglycerides.

Question 17

Exmplain why triglycerides are not considered to be polymers.

Answer 17

Long polymer chains Cannot be created as 3 fatty acids attach to create an Ester bond.

Question 18

Describe a test you could carry out to show that a piece of coconut contains lipids.

Answer 18

Crush the coconut in ethanol and add to water.

A white emulsion will be produced if lipids are present.

Question 19

Describe how a phospholipid differs from a triglyceride.

Answer 19

Phospholipid has a phosphate and only two fatty acids.

Question 20

Give ways starch molecules are adapted for their function in a plant cell.

Answer 20

They are insoluble and therefore don’t affect water potential.

They are helical and compact.

They are large molecules and therefore can’t leave the cells.

Question 21

Explain how cellulose molecules are adapted for their functions in plant cells.

Answer 21

They are long and straight chains that become linked together by many hydrogen bonds o form fibrils. This provides strength for the cell wall.

Question 22

Name the reaction that breaks carbohydrates down into their monomers.

Answer 22

Hydrolysis.

Question 23

Give features of starch and explain how this helps it act as a storage substance.

Answer 23

They are helical shaped so are therefore compact and tightly packed so lots can fit into a small place.
They are insoluble so have no somatic effect and don’t leave the cell or affect water potential.

Question 24

Explain one way in which the structure of cellulose is linked to its function.

Answer 24

It has a glycosidic beta 1-4 bond

Question 25

Why is sucrose classified as a carbohydrate ?

Answer 25

Carbon and hydrogen are in a 2:1 ratio which is the same proportions as in water.

Question 26

What type of reaction breaks down sucrose into monosaccharides ?

Answer 26

Hydrolysis.

Question 27

How does the test for lipids Work ?

Answer 27

Lipids dissolve in ethanol due to being soluble in alcohol

But then form a white precipitate in water due to being insoluble in water.