Lipids 1A Flashcards
What is a tryglyceride
a type of lipid
What is the structure of a lipid
A molecule of glycerol bonded to three fatty acid molecules
Fatty Acid structure
long “tails” made of hydrocarbons which are hydrophobic. These tails make lipids insouble in water. All fatty acids have same basic structure but the hydrocarbon tail varies. Carbon atom links fatty acid to glycerol OH atom and R group hydrocarbon tail
What is an ester bond
A bond which forms when a triglyceride is formed via 3 condensation reactions ester bond forms 3 times
What is the difference between a saturated and unsaturated fatty acid
Difference is in their R groups
Saturated - no double bonds between carbon atoms
Unsaturated - at least one double bond between carbon atoms
How are phospholipids similar to triglycerides
One of the fatty acids is replaced by a phosphate group. Phosphate group is hydrophilic and the fatty acids are hydrophobic
Triglyceride function
Energy storage molecules
Long hydrocarbon tails of the fatty acids contain lots of chemical energy.
Insoluble - does not affect water potential
Phospholipids function
Make up the bilayer of cell membranes
Hydrophilic heads
Hydrophobic tails so they form a double layer with their heads facing out
Centre of bilayer is hydrophobic so water soluble substances cannot pass through
What is the test for lipids
Emulsion Test: Shake sample with ethanol until it dissolves then pour the sample into water. If lipid is present then a milky emulsion will form. The greater the volume of lipid then the more noticeable the milky emulsion will be
