1.3 Lipids

Question 1

What are the 3 elements that make up lipids

Answer 1

• Carbon
• Hydrogen
• Oxygen

Question 1

What are lipids insoluble in

Answer 1

Water

Question 2

What are lipids soluble in

Answer 2

Organic solvents like ethanol

Question 3

What are the 7 functions of lipids

Answer 3

• Thermal insulation
• Protection
• Buoyancy
• Source of metabolic water
• Waterproofing
• Energy store
• Cell membrane structure

Question 4

What is denser lipids or water

Answer 4

Water is denser than lipids

Question 5

What waterproof organisms’ layers come from lipids

Answer 5

-Skin
- Leaf cuticle
- Fur
- Feather

Question 6

What type of tissue creates thermal insulation, lipids

Answer 6

Adipose tissue

Question 7

What 2 things in the cell membrane are lipids

Answer 7

• Phospholipid bilayer
• Cholesterol

Question 8

What are the 2 types of lipid structure

Answer 8

• Simple
• Compound

Question 9

In a simple lipid, what are the 2 components

Answer 9

• Glycerol
• Fatty acids

Question 10

In a compound lipid, what are the components

Answer 10

• Glycerol
• Fatty acids
• Another group/ molecule/ compound

Question 11

What is an example of a simple lipid

Answer 11

Triglyceride

Question 12

What is an example of a compound lipid

Answer 12

Phospholipid

Question 13

What is the chemical formula for glycerol

Answer 13

C3H8O3

Question 14

What is the general formula for fatty acids

Answer 14

CH3(CH2)nCOOH

Question 15

In fatty acids, which part of the general formula is the variable/ R group

Answer 15

The elements in a bracket e.g. (CH2)n

Question 16

In fatty acids, which part of the general formula is the carboxyl group

Answer 16

COOH

Question 17

In a fatty acid how is the carboxyl group bonded

Answer 17

HO-C=O

Question 18

In lipid structure, what bond is formed by a condensation reaction

Answer 18

Ester bond

Question 19

Does an ester bond contain an oxygen bridge

Answer 19

Yes

Question 20

Are lipids polymers, and why

Answer 20

Not polymers because they aren’t made from the same repeated units

Question 21

How do the hydrocarbon tail and the fatty acid tail differ in lipids

Answer 21

The hydrocarbon tail only contains carbon and hydrogen so doesn’t have a carboxyl group (COOH) whereas the fatty acid tail does contain the carboxyl group

Question 22

Why are some fatty acids saturated

Answer 22

• A saturated fatty acid is fully saturated with hydrogen because there are no carbon to carbon double bonds

Question 23

Why are some fatty acids unsaturated

Answer 23

• An unsaturated fatty acid isn’t fully saturated with hydrogen because there is at least one carbon to carbon double bond

Question 24

Name an example of a saturated fat

Answer 24

Butter

Question 25

Name an example of an unsaturated fat

Answer 25

Oil

Question 26

Where do saturated fats usually come from

Answer 26

Animals

Question 27

Where do unsaturated fats usually come from

Answer 27

Plants

Question 28

At room temp, what state are saturated fats

Answer 28

Solid

Question 29

At room temp, what state are unsaturated fats

Answer 29

Liquid

Question 30

What does a high increase of saturated fats increase your risk of

Answer 30

Heart disease

Question 31

What is a respiratory substrate

Answer 31

A molecule that can release energy which is used to create ATP

Question 32

How do animals get their energy from a respiratory substrate

Answer 32

By breaking it down in the presence of oxygen, oxidising it

Question 33

When you oxidies a lipid respiratory substrate, where does the energy come from

Answer 33

The breaking of the C-C and C-H bondds

Question 34

Why do you get twice the energy yield from using lipids instead of carbohydrates as a respiratory substrate

Answer 34

Because there are more C-C and C-H bonds in lipids due to the hydrocarbon tail

Question 35

Are phospholipids, a compound or simple lipid

Answer 35

Compound lipid

Question 36

What are the 2 components of a phospholipid

Answer 36

- x2 Hydrophobic tails - x1 Hydrophilic head

Question 37

What is the head made of in a triglyceride

Answer 37

Glycerol

Question 38

What is the head made of in a phospholipid

Answer 38

- Glycerol - Phosphate

Question 39

How many tails does a triglyceride have

Answer 39

3

Question 40

How many tails does a phospholipid have

Answer 40

2

Question 41

Why do fats form good waterproofing layers

Answer 41

They're insoluble in water

Question 42

What is the structure of a tiglyceride

Answer 42

- 1 Glycerol - 3 fatty acids

Question 43

What chemical group does glycerol belong to

Answer 43

Alcohol

Question 44

What are the 2 different types of fatty acids

Answer 44

- Saturated - Unsaturated

Question 45

In a triglyceride, what is the name of the covalent bond that forms between a fatty acid and glycerol

Answer 45

Ester bond

Question 46

What type of reaction takes place when ester bonds form

Answer 46

Condensation reaction

Question 47

Name the biochemical test that is used to show the presence of lipids

Answer 47

Emulsion test

Question 48

Describe how you would use a microscope to find the mean diameter of triglyercide droplet on a slide

Answer 48

- Measure with eyepiece graticule / scale; - Calibrate with stage micrometer / scale on slide / object of known size - Repeats and calculate the mean;

Question 49

Explain why phospholipids can form a bilayer but triglycerides cannot (3 marks)

Answer 49

- Phospholipids both hydrophobic and hydrophilic - Triglycerides only hydrophobic - Hydrophilic group attracts to water

Question 50

Describe how a triglyceride molecule is formed (3 marks)

Answer 50

1. One glycerol and three fatty acids; 2. Condensation (reactions) and removal of three molecules of water; 3. Ester bond(s) (formed);