lipids

Question 1

what are macromolecules?
what are the macromolecules?

Answer 1

complex molecules, relatively large molecular mass - containing very large number of atoms

triglycerides
phospholipids

Question 2

what chemical elements do lipids contain?

Answer 2

C H O

Question 3

what are the named types of lipid? [3]

Answer 3

1) triglycerides
2) phospholipids
3) cholesterol

Question 4

what is the structure of a triglyceride?(draw)
circle the * bond

Answer 4

1 glycerol 3 fatty acids
text book pg 54

Question 5

what is glycerol?
draw the structure of glycerol

Answer 5

alcohol
text book pg 54

Question 6

what is a fatty acid?
draw the structure

Answer 6

carboxylic acid with long tail hydrocarbons attached
=hydrophobic

page 24 revision guide

Question 7

what bond is used to join fatty acids to glycerol?
what chemical elements are within the ester bond on a triglyceride?

Answer 7

ester bonds
O-C=O

Question 8

what reaction happens to make a triglyceride?

Answer 8

synthesis:
esterification (type of condensation)
H + HO interact forming 3 water molecules

Question 9

how are triglycerides broken down?

Answer 9

hydrolysis reaction
3 water molecules
= 1 glycerol, 3 fatty acids

Question 10

what are the types of fatty acids? [2]

Answer 10

unsaturated
saturated

Question 11

what’s a saturated fatty acid?

Answer 11

fatty acid chains with no double bonds between carbon atoms because they are saturated with hydrogen atoms

Question 12

what’s an unsaturated fatty acid?

Answer 12

fatty acid chain with double bond(s) between carbon atoms, creates kink/bend
known as oils, liquid at room temp

Question 13

whats the structure for a phospholipid?

Answer 13

1 phosphate group (hydrophilic)
1 glycerol
2 fatty acids (hydrophobic)

text book pg 55

Question 14

what are the properties of triglycerides? [4]

Answer 14

• animals+plants- energy storage molecules
• bacteria use triglycerides to store energy and
carbon
• long hydrocarbon tails of fatty acids-contain lots of chemical energy and energy is released when they’re broken down
• insoluble so water cant enter the cells by osmosis which would make them swell, the phosphate group face outside protecting the fatty acid tails

Question 15

what are the properties of phospholipids? [3]

Answer 15

• phospholipid bilayer

• centre of bilayer is hydrophobic-water soluble substances can’t easily pass through, acts as a barrier to substances.

• in all cell membranes of eukaryotes and prokaryotes, made of phospholipid bilayer, controls what enters and leave the cell.

Question 16

what’s the structure of cholesterol?

Answer 16

• hydrocarbon ring structure attached to hydrocarbon tail.
• ring structure has a polar hydroxyl group attached.

Question 17

what’s the properties of cholesterol? [4]

Answer 17

eukaryotic cells:
• regulate/stablises fluidity of cell membrane by interacting with phospholipid bilayer

• small size, flattened shape- fits between phospholipid molecules in the membrane.

• high temp-bind to hydrophobic tails of phospholipids so they pack closer together= membrane less fluid, more rigid
• low temp-prevents phospholipids packing close together, increases membrane fluidity

Question 18

what are the functions of triglycerides in living organisms? [name 3]

Answer 18

• energy source for respiration
• thermal insulation to reduce heat loss
• electrical insulation for impulse transmission
• cushioning effect to protect vital organs
• buoyancy
• membrane formation>hydrophobic barriers

(hormone production)

Question 19

what are glycolipids?

Answer 19

in membranes lipids with attached carbohydrate chains

Question 20

what are the types of saturation? [2]

Answer 20

monounsaturated- 1 double bond between carbon atoms
polyunsaturated- 2(+) double bonds between carbon atoms

Question 21

what’s the general formula for:
saturated fatty acid?

Answer 21

CnH2n + 1COOH

Question 22

how does the structure of phospholipids allow them to form the bilayer of a plasma membrane? [3]

Answer 22

-hydrophobic tail is repelled by water
-hydrophilic head is forms hydrogen bonds with water
-therefore hydrophobic tails face inwards facing each other and hydrophilic heads face outwards, forming bilayer

Question 23

how do the structures and properties of lipids suit them to their role as enegrry storage molecules in plants and animals. [7]

Answer 23

1) lots of carbon-carbon bonds
2) have lots of energy per molecule
3) more energy can be stored in small space

4) insoluble
5) don’t affect water potential of the cell

6) fatty acids are long carbon chains
7) can be broken down to release carbon

Question 24

what is less dense protein or lipid?

Answer 24

more dense=protein
less dense=lipid

Question 25

are lipids soluble or insoluble?

Answer 25

INSOLUBLE

Question 26

what does cholesterol synthesise? (2)

Answer 26

steroid hormone
bile