lipids Flashcards
what are macromolecules?
what are the macromolecules?
complex molecules, relatively large molecular mass - containing very large number of atoms
triglycerides
phospholipids
what chemical elements do lipids contain?
C H O
what are the named types of lipid? [3]
1) triglycerides
2) phospholipids
3) cholesterol
what is the structure of a triglyceride?(draw)
circle the * bond
1 glycerol 3 fatty acids
text book pg 54
what is glycerol?
draw the structure of glycerol
alcohol
text book pg 54
what is a fatty acid?
draw the structure
carboxylic acid with long tail hydrocarbons attached
=hydrophobic
page 24 revision guide
what bond is used to join fatty acids to glycerol?
what chemical elements are within the ester bond on a triglyceride?
ester bonds
O-C=O
what reaction happens to make a triglyceride?
synthesis:
esterification (type of condensation)
H + HO interact forming 3 water molecules
how are triglycerides broken down?
hydrolysis reaction
3 water molecules
= 1 glycerol, 3 fatty acids
what are the types of fatty acids? [2]
unsaturated
saturated
what’s a saturated fatty acid?
fatty acid chains with no double bonds between carbon atoms because they are saturated with hydrogen atoms
what’s an unsaturated fatty acid?
fatty acid chain with double bond(s) between carbon atoms, creates kink/bend
known as oils, liquid at room temp
whats the structure for a phospholipid?
1 phosphate group (hydrophilic)
1 glycerol
2 fatty acids (hydrophobic)
text book pg 55
what are the properties of triglycerides? [4]
• 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
what are the properties of phospholipids? [3]
• 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.
what’s the structure of cholesterol?
- hydrocarbon ring structure attached to hydrocarbon tail.
- ring structure has a polar hydroxyl group attached.
what’s the properties of cholesterol? [4]
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
what are the functions of triglycerides in living organisms? [name 3]
- 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)
what are glycolipids?
in membranes lipids with attached carbohydrate chains
what are the types of saturation? [2]
monounsaturated- 1 double bond between carbon atoms
polyunsaturated- 2(+) double bonds between carbon atoms
what’s the general formula for:
saturated fatty acid?
CnH2n + 1COOH
how does the structure of phospholipids allow them to form the bilayer of a plasma membrane? [3]
-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
how do the structures and properties of lipids suit them to their role as enegrry storage molecules in plants and animals. [7]
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
what is less dense protein or lipid?
more dense=protein
less dense=lipid
are lipids soluble or insoluble?
INSOLUBLE
what does cholesterol synthesise? (2)
steroid hormone
bile
