Lipids Flashcards
(18 cards)
Explain what are polymers, monomers and give examples of both
A monomer is a small basic molecular unit which larger molecules are made of
polymers are large complex molecules composed of long chains of monomers joined together
monomers:monosaccharides, amino acids and nucleotides
polymers: carbohydrates
what are the two groups of lipids
triglycerides and phospholipids
How are triglycerides made
triglycerides are formed by the condensation reaction of of one molecule of glycerol and three molecules of fatty acids attached to it
what do the fatty acids moleucles have
they each have long tails made of hydrocarbon they are hydrophobic
why are lipids insoluble in water
because of the hyrophobic tail
what do all fatty acids have
they all have the dame basic structure but the hydrocarbon tail varies
how are triglycerides formed
A condensation reaction between glycerol and a fatty acid (RCOOH) forms an ester bond.
What are the two different fatty acid and what makes them different
The R-group of a fatty acid may be saturated or unsaturated.Difference is the hydrocarbon tail the R group
what are saturated fatty acids
they have a single bonds between carbon atoms they are said to be saturated with hydrogen
what are unsaturated fatty acids
they have a double bonds with carbon atoms and are said to kink-the molecules are not packed together tightly
explain phospholipids
they are found in the cell membranes
how are phospholipids different to triglycerides
phospholipids have one glycerol molecule ,bonded with two fatty acids( ester bonds ) and one phosphate group
explain the phosphate group and the fatty acids to help the phospholipids
the phosphate group is hydrophilic and the fatty acids tail is hydrophobic
how does phospholipids structure helps with the function
the heads(phosphate group ) are hydrophilic and the tails( hydrocarbon) are hydrophobic they will form a double layer the heads will face out towards water- attracted to it
how do phospholipids make the bilayer found in cell membranes
the tails will face inwards and so the centre of the bilayer is hydrophobic and the heads outwards (water cannot pass through easily) membrane is a barrier to those substances
How are triglcerides structure helpful as a energy storage molecule
their hydrocarbon tail contains lots of chemical energy which will be realises when broke down. This is why lipids contain twice as much energy than carbohydrates.
How does the structure help for function- triglycerides
they are insoluble so it won’t affect the cells water potential as water cannot enter via osmosis.
They are also clumped up together as insoluble droplets since the hydrophobic tail will face inwards and the glycerol head will protect from any water entering.
Emulsion test
For lipids:
add the test substances with ethanol then shake for a minute and then pour water into the solution
if positive then It will show up as a milky emulsion
the more lipid concentration the more milky it will appear.
