Lipids Flashcards
what elements do lipids contain?
carbon, hydrogen and oxygen
which have less oxygen lipids or carbohydrates?
lipids
are lipids polar or non-polar?
non-polar
are lipids soluble in water?
no
what will lipids dissolve in?
organic solvents such as alcohol
Due to lipids being non-polar and insoluble in water what are they described to be?
hydrophobic
what 2 molecules are lipids made up of?
fatty acids and glycerol
what are the names of the 2 types of lipids?
triglycerides and phospholipids
what are fatty acids?
- long chains of carbon and hydrogen atoms
- carboxyl group at one end (COOH)
what is a saturated fatty acid?
contains no c=c bond
what is an unsaturated fatty acid?
contains at least 1 c=c bond
- 1 c=c bond is monosaturated
- 2+ c=c bond is polysaturated
what is the structure of a saturated fatty acid?
straight shape so they can be tightly packed, therefore they’re solid
what’s the structure of an unsaturated fatty acid?
the chain kinks where the c=c bond is so they can’t be packed as tightly therefore they’re in a liquid state
what are triglycerides made up of?
3 fatty acids and 1 glycerol
what bonds attach the fatty acids to the glycerol?
ester bonds via a condensation reaction (remove 3 water)
what does the condensation reaction on a triglycerides occur between?
the carboxyl group (COOH) on the fatty acid and the hydroxyl group (OH) on the glycerol
why are triglycerides a good energy storage?
lots of C-H bonds that store lots of energy
how can triglycerides act as a metabolic water source?
they release water when they’re oxidised
why is the fact that lipids are large and hydrophobic an advantage?
they won’t effect the water potential and osmosis in a cell
why is it good lipids are low in mass?
a lot can be stored in an animal without increasing mass
what are phospholipids made up of?
a glycerol, 2 fatty acids and a phosphate group
how do the 2 fatty acids bond to the glycerol?
via 2 condensation reactions (release 2 water molecules) forming 2 ester bonds
what’s the phosphate molecule described as?
- hydrophilic head (towards the water as it is charged)
- as it’s charged it repels other fats
what’s the fatty acid chain described as?
the hydrophobic tail as it repels water but will mix with fats
what’s is a phospholipid described as?
polar due to the 2 regions acting differently
how are phospholipids positioned?
the heads are exposed to water
the tails are away from the water
what does the movement in a phospholipid form?
a phospholipid bilayer which forms the plasma membrane around cells
- hydrophilic phosphate head enables the surface of the plasma membrane to stay in place
why is the phospholipid bilayer arrangement an advantage?
enables carbohydrates to attach and form important receptors on the membrane (glycolipids)
how would you test for the presence of a lipid?
- Add 2cm3 of the sample to a test tube
- Add 5cm3 of ethanol and shake to dissolve the sample
- Add 5cm3 of water and shake
Positive Result = cloudy-white solution
