Lipids 1A

Question 1

What is a tryglyceride

Answer 1

a type of lipid

Question 2

What is the structure of a lipid

Answer 2

A molecule of glycerol bonded to three fatty acid molecules

Question 3

Fatty Acid structure

Answer 3

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

Question 4

What is an ester bond

Answer 4

A bond which forms when a triglyceride is formed via 3 condensation reactions ester bond forms 3 times

Question 5

What is the difference between a saturated and unsaturated fatty acid

Answer 5

Difference is in their R groups
Saturated - no double bonds between carbon atoms
Unsaturated - at least one double bond between carbon atoms

Question 6

How are phospholipids similar to triglycerides

Answer 6

One of the fatty acids is replaced by a phosphate group. Phosphate group is hydrophilic and the fatty acids are hydrophobic

Question 7

Triglyceride function

Answer 7

Energy storage molecules
Long hydrocarbon tails of the fatty acids contain lots of chemical energy.
Insoluble - does not affect water potential

Question 8

Phospholipids function

Answer 8

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

Question 9

What is the test for lipids

Answer 9

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