lipids (biomols) Flashcards
what state of matter is fat in at room temp
solid
what state of matter is oils in at room temp
liquids
what elements are lipids made of
carbon, hydrogen, oxygen (same as carbs but proportion of o2 is lower)
what are lipids soluble in and what are they not soluble in
organic solvents (alcohols) BUT NOT IN WATER
why are lipids not soluble in water
lipids are non polar, so the charges across the molecule are balanced, so they dont from hydrogen bonds with polar water molecules. THEY ARE HYDROPHOBIC.
WHAT IS THE STRUCTURE OF A SIMPLE LIPID
ONE GLYCEROL MOLECULE + 3 FATTY ACIDS = TRIGLYCERIDE
WHAT IS A GLYCEROL
A SIMPLE ALCOHOL (SO IT HAS THE OH GROUP)
WHAT ARE FATTY ACIDS
THEY ARE LONG HYDROCARBON CHAINS WITH AN ACID GROUP (COOH) AT ONE END
HIW DOES A TRIGLYCERIDE FORM
3 FATTY ACIDS LINE UP NEXT TO A GLYCEROL MOLCULE. THE OH GROUPS ON THE FATTY ACIDS ARE LINED UP NEXT TO THE OH GROUPS ON THE GLYCEROL, ALLOWING 3 CONDENSATION REACTIONS TO OCCUR, 3 WATER MOLS ARE LOST, 3 ESTER BONDS ARE FORMED
WHAT BONDS ARE IN TRIGLYCERIDES
ESTER BONDS
HOW DO U BREAK A SIMPLE LIPID APART
ADD 3 WATER MOLS AND AN ENZYME TO BRING ABT A HYDROLYSIS REACTION
WHAT DOES IT MEAN TO HAVE A SATURATED FATTY ACID
NO DOUBLE BONDS BETWEEN CARBON ATOMS (STRAIGHT CHAIN)
WHAT DOES IT MEAN TO HAVE A MONOSATURATED FATTY ACID
ONE DOUBLE BOND BETWEEN CARBON ATOMS (BENDS)
WHAT DOES IT MEAN TO HAVE A POLYSATURATED FATTY ACID
MORE THAN ONE DOUBLE BOND BETWEEN CARBON ATOMS (BENDS)
what do double bonds in fatty acids cause
it causes the fatty acids to bend
what makes the lipid structure a liquid (oil)
the more double bonds the more fluid (less rigid) the lipod structure will be. this is bcos the double bonds cause the fatty acids to ben, whuch prevents them ffrom packing as closelytg when they form as a lipid
what makes a lipid a solid (a fat)
no double bonds present
are lipids polymers
no
why are lipids not polymers
a polymer is made up of many similar monomers. a simple lipid is not. a lipid is made up of one glycerol and 3 fatty acids
what are some roles of lipids
- buoyancy for aquatic animals
- thermal insulation
- creation of hydrophobic barriers
- waterproofing on bird feathers (theyre hydrophobic)
- energy sources (theyre easily hydrolysed when energy is needed by a cell) (the fatty acids + glycerol can then be respired to release energy, and they release twice as much energy as carbs)
- energy stores (stoored in fat cells in the andipose tissue of animals, and as lipid droplets in plant cells - the long HC chains contain alot of energy)
what is a phospholipid
a modified triglycerides containing phosporous. one of the 3 fatty acids is replaced by a phosphate group.
what is the structure of a phospholipid
they have a hydrophilic head which are attracted to water (phosphate group)
they have a hydrophobic tail which are replelled by water (the fatty acids)
what parts of a phospholipid are polar
the phosphate head (hydrophilic) are polar
and the fatty acid tails (hydrophobic) are non polar
what happens when lipids are dropped into water
they form spheres - “micelles”
a cell has water both inside the cytoplasm and outside (tissue fluid). how do the phospholipods arrange themselves when ttheyf rom the cell membrane (phospholipid bilayer)
phosphate head facing outside tissue fluid. fatty acid tails facing the other fatty acid tails with the other phosphate head facing the cytoplasm
what are sterols
thse are based on complex alcohol molecules. they have hydrophilic and hydrophobic regions
whats an example of a sterol
cholesterol
why do we need cholesterol in our body
important component of cell membrane structure. the flattened shape of cholesterol allows it to fit between the fatty acid tails in the phospholipids to stabilise the sttrcuture of the membrane. by regulating the fluidity of the membrane it limits the movement of the phospholipids (side to side), w the hydrophilic regions toward the outside of the membrane.
what else is chlolesterol needed for in our body
cholesterol is neede to make steroid hormones in the body
egs) sex hormones - oestrogen, progesterone, testosterone
whats the test for lipids
the emulsion test - add 2cm of sample and 2cm of ethanol to a test tube. if lipid present, cloudy white emulsion will be seen
