4

Question 1

Lipids are …, they all contain the elements carbon, hydrogen and oxygen.

Answer 1

macromolecules

Question 2

… have one molecule of glycerol with three fatty acids attached to it.

Answer 2

triglycerides

Question 3

Triglycerides are synthesised by the formation of an … bond between each fatty acid and the glycerol molecule.

Answer 3

ester

Question 4

One triglyceride molecule has … ester bonds.

Answer 4

three

Question 5

Each ester bond is formed by a … reaction.

Answer 5

condensation

Question 6

The process in which triglycerides are synthesised is called …

Answer 6

esterification

Question 7

The process in which triglycerides are synthesised is called …

Answer 7

esterification

Question 8

Triglycerides break down when the … bonds are broken.

Answer 8

ester

Question 9

Each ester bond is broken in a … reaction (in which a water molecule is used up).

Answer 9

hydrolysis

Question 10

The variable … group can be any hydrocarbon

Answer 10

R

Question 11

Fatty acid molecules have long ‘tails’ made of …

Answer 11

hydrocarbons

Question 12

Fatty acid molecules have long ‘tails’ made of …

Answer 12

hydrocarbons

Question 13

The fatty acid tails are … (they repel water molecules).

Answer 13

hydrophobic

Question 14

These tails make … insoluble in water.

Answer 14

lipids

Question 15

All fatty acids have the same basic structure, but the hydrocarbon … varies.

Answer 15

tail

Question 16

There are two kinds of fatty acids - saturated and unsaturated - the difference is in their … tails.

Answer 16

hydrocarbon

Question 17

Saturated fatty acids don’t have any … bonds between their carbon atoms in their hydrocarbon tails.

Answer 17

double

Question 18

Unsaturated fatty acids have at least one … bond between carbon atoms, which causes the chain to kink.

Answer 18

double

Question 19

Most animal fats are … - the fatty acids in these lipids are saturated so they have no double bonds.

Answer 19

saturated

Question 20

Most plant fats are … - some of the fatty acids in these lipids are unsaturated meaning they have double bonds.

Answer 20

unsaturated

Question 20

Most plant fats are … - some of the fatty acids in these lipids are unsaturated meaning they have double bonds.

Answer 20

unsaturated

Question 21

Each phospholipid has a … group.

Answer 21

phosphate

Question 22

In a … ring structure, the carbon atoms are literally arranged in a ring-like shape instead of a ling chain.

Answer 22

hydrocarbon

Question 23

Phospholipids are pretty similar to triglycerides, except one of the fatty acid moleculesis replaced by a … group.

Answer 23

phosphate

Question 24

The phosphate group is ... (it attracts water molecules).

Answer 24

hydrophilic

Question 25

Cholesterol is another type of ...

Answer 25

lipid

Question 26

Cholesterol has a hydrocarbon ... structure attatched to a hydrocarbon tail.

Answer 26

ring

Question 27

The ring structure has a ... hydroxyl (OH) group attached to it.

Answer 27

polar

Question 28

In animals and plants, ... are mainly used as energy storage molecules.

Answer 28

triglycerides

Question 29

Some ... use triglycerides to store both energy and carbon.

Answer 29

bacteria

Question 30

Triglycerides are good for storage because the long hydrocarbon tails of the fatty acids contain lots of ... energy - a load of energy is released when they're broken down.

Answer 30

chemical

Question 31

Because of these tails, lipids contain about twice as much energy per gram as ...

Answer 31

carbohydrates

Question 32

Storage molecules also need to be ... because otherwise they'd just dissolve (and release whatever they were storing) whenever they came into contact with water.

Answer 32

insoluble

Question 33

Triglycerides are also _________, so they don't cause water to enter the cells by osmosis, which would make them swell.

Answer 33

insoluble

Question 34

The triglycerides bundle together as insoluble droplets in cells because the fatty acid tails are ... - the tails face inwards, shielding themselves from water with their glycerol heads.

Answer 34

hydrophobic

Question 35

Phospholipids are found in the cell ... of all eukaryotes and prokaryotes.

Answer 35

membrane

Question 36

Phospholipids make up what's known as the phospholipid ...

Answer 36

bilayer

Question 37

Cell ... control what enters and leaves a cell.

Answer 37

membranes

Question 38

Phospholipid heads are hydrophilic and their tails are ..., so they form a double layer with their heads facing out towards the water on either side.

Answer 38

hydrophobic

Question 39

Phospholipid heads are hydrophilic and their tails are ..., so they form a double layer with their heads facing out towards the water on either side.

Answer 39

hydrophobic

Question 40

The centre of the bilayer is hydrophobic, so water-soluble substances can't easily pass through it - the ... acts as a barrier to those substances.

Answer 40

membrane

Question 41

In eukaryotic cells, cholesterol molecules help ... the cell membrane by interacting with the phospholipid bilayer.

Answer 41

strengthen

Question 42

In eukaryotic cells, ... molecules help strengthen the cell membrane by interacting with the phospholipid bilayer,

Answer 42

cholesterol

Question 43

Cholesterol has a small size and ... shape - this allows cholesterol to fit in between the phospholipid molecules in the membrane.

Answer 43

flattened

Question 44

Cholesterol binds to the hydrophobic tails of the ... causing them to pack more closely together. This helps to make the membrane less fluid and more rigid.

Answer 44

phospholipids

Question 45

At ... temperatures, cholesterol prevents phospholipids from packing too close together and so increases membrane fluidity

Answer 45

lower

Question 46

At ... temperatures, cholesterol prevents phospholipids from packing too close together and so increases membrane fluidity

Answer 46

lower