3.1.3 Lipids

Question 1

What are they the only molecules not to be made up of

Answer 1

polymers

Question 2

What are the 3 groups of lipids

Answer 2

Fats
Phospholipids
Steroids

Question 3

4 properties all lipids share

Answer 3

Made from carbon, oxygen and hydrogen
Have less oxygen than carbohydrates
Insoluble in water (hydrophobic)
Soluble in alcohol and acetone (organic solvents)

Question 4

5 things lipids do

Answer 4

Cell membranes
Protection
Insulation
Energy
Waterproofing

Question 5

What lipids are in cell membranes

What do they do there

Answer 5

Phospholipids

Provide flexibility and control substance movements

Question 6

What lipids provide protection and where

Answer 6

Fat around delicate organs

Question 7

What lipids are used for insulation in the body

Why

Answer 7

Fats
They’re slow heat conductors so a thin layer preserves heat
Insulates neurones (myelin sheath) - adipose tissue

Question 8

What lipids are used for energy when they’re oxidised, what do they do

Answer 8

Fats

Release x2 energy of carbohydrates whilst releasing water

Question 9

What do plants and animals rely on to make them waterproof

Answer 9

Waxy cuticles

Question 10

What lipids do mammals release

Answer 10

Oily secretion

Question 11

What’s the correct name for fats

Answer 11

Triglycerides

Question 12

What’s the structure of 1 triglyceride

Answer 12

3 fatty acid chains bonded to a glycerol backbone

Question 13

What are triglycerides in

Answer 13

Butter, oils, foods

Question 14

What’s glycerol

Answer 14

An alcohol formed from 3 carbons

Question 15

What does each carbon atom have attached to it in a triglyceride

Answer 15

A hydroxyl group

Question 16

What’s glycerol bound to in a triglyceride

Answer 16

3 fatty acids

Question 17

What are fatty acids formed from

Answer 17

Long hydrocarbon chains (usually 16-18 carbons)

Question 18

What do fatty acids end in

Answer 18

A carboxyl group (COOH)

Question 19

What are carboxyl groups

Answer 19

Oxygen double bonded to carbon double bonded to hydroxyl group (-COOH)

Question 20

How many different fatty acids are there

Answer 20

Over 70

Question 21

What will each different triglyceride have different and the same

Answer 21

Same glycerol

Different fatty acid attached to glycerol

Question 22

What type of molecules are triglycerides

Answer 22

Non-polar

Question 23

What do polar molecules have

Answer 23

2 ends (poles) that behave differently from one another e.g 1 side +, 1 side -

Question 24

Is water polar or non-polar and how

Answer 24

Polar

Hydrogen is slightly positive and oxygen is negative due to electron distribution

Question 25

What do hydrogen and oxygen in water bond with

Answer 25

Substances that dissolve in water

Question 26

What are triglycerides unable to do as they're non-polar

Answer 26

Form hydrogen bonds with water

Question 27

What are 3 fatty acids bound to the glycerol by

Answer 27

Ester linkages

Question 28

What reaction forms triglycerides | What is released

Answer 28

Condensation reaction | Water

Question 29

What are ester linkages broken down by

Answer 29

Hydrolysis

Question 30

How many water molecules are released when a triglyceride is formed Why

Answer 30

3 | 1 molecule released from each ester linkage

Question 31

What triglyceride is the worst fat

Answer 31

Saturated

Question 32

What do Saturated triglyceride chains look like

Answer 32

Straight

Question 33

What do unSaturated triglyceride chains look like

Answer 33

Have a kink in

Question 34

Which fats are mostly all saturated

Answer 34

Animal fats

Question 35

What are saturated triglycerides normally at room temperature

Answer 35

Solids

Question 36

What is the difference between saturated and unSaturated triglycerides

Answer 36

Saturated - no double bonds so maximum number of hydrogens UnSaturated - double bonds between some carbons so more hydrogen could bind

Question 37

What's a triglyceride with 1 carbon-carbon double bond (C=C)

Answer 37

Monounsaturated fatty acid

Question 38

What's a triglyceride with more than 1 carbon-carbon double bond (C=C)

Answer 38

Polyunsaturated fatty acid

Question 39

Example of unSaturated fats

Answer 39

Most plant/fish fats

Question 40

What are unSaturated fatty acids at room temperature

Answer 40

Oils

Question 41

What type of molecules are phospholipids

Answer 41

Individual molecules

Question 42

Where are phospholipids

Answer 42

In cell membranes

Question 43

Similarity between triglycerides and phospholipids

Answer 43

Both based on glycerol

Question 44

Difference between triglycerides and phospholipids

Answer 44

Phospholipids Only have 2 fatty acids instead of 3, 1 replaced by a phosphate group

Question 45

Which part of a phospholipid is the phosphate group | How does it act around water

Answer 45

Head | Hydrophilic

Question 46

Which part of a phospholipid are the 2 fatty acids | How does it act around water

Answer 46

Tails | Hydrophobic

Question 47

What's the shoulder of a phospholipid

Answer 47

Glycerol

Question 48

What bond is the phosphate group

Answer 48

Ionic

Question 49

What bond are the fatty acids

Answer 49

Covalent

Question 50

How do phospholipids arrange in water

Answer 50

Into a bilayer

Question 51

Which way do the heads and tails face

Answer 51

Heads - outwards | Tails - inwards

Question 52

Are phospholipids polar or non-polar | Why

Answer 52

Polar | Have 2 ends (poles) that act differently

Question 53

Why are phospholipids vital parts of the cell membrane

Answer 53

As their bilayer creates a barrier

Question 54

What does hydrophilic and hydrophobic involve as well as water

Answer 54

Cytoplasm

Question 55

What's the test of lipids

Answer 55

The emulsion test

Question 56

What's the emulsion test based on

Answer 56

The fact they're insoluble in water

Question 57

What's the method for the emulsion test

Answer 57

``` Use a dry test tube (no grease/oil) Add 2ml of the solution to test Add 3ml ethanol Shake sample to dissolve any present lipids Filter mixture if necessary Add 5ml water + shake gently ```

Question 58

What's the result of the emulsion test

Answer 58

Any filtrate not dissolved in water forms an emulsion at top (milky white colour due to fat droplets refracting light)

Question 59

Exposing test tube at end of emulsion test

Answer 59

Fat + ethanol at top (milky white emulsion) | Water at bottom