Lipids

Question 1

name 2 groups of lipids (2 marks)

Answer 1

triglycerides
phospholipids

Question 2

structure of fatty acid/lipid (2 marks)

Answer 2

-R variable hydrocarbon group
-COOH carboxyl group

Question 3

draw the 2 types of fatty acid/lipid (2 marks)

Answer 3

check google

Question 4

staurated vs unsaturated (2 marks)

Answer 4

saturated is single bond
unsaturated is double C=C bond

Question 5

describe how triglycerides form
4 marks

Answer 5

-1 glycerol molecule and 3 fatty acids
-condesnation reaction
-removing 3 water molecules
-forming 3 ester bonds

Question 6

describe how phospholipids form (1 marks)

Answer 6

-1 glycerol molecule , 2 fatty acids and 1 phosphate group

Question 7

function of triglycerides (1 marks)

Answer 7

energy storage

Question 8

properties of triglycerides relation to structure (4 marks)

Answer 8

-high ratio of C-H bonds to carbon atoms in hydrocarbon chain
->so used in respiration to release more energy than carbohydrate
-hydrophobic fatty acid insoluble in water
->so no effect of water potential of cell

Question 9

properties of phosphlipid relation to structure (4 marks)

Answer 9

-hydrophillic phosphate head
->attarcts water so point outwards
-hydrophobc fatty acid tails
->repells water so points inwards

Question 10

difference in triglycerides and phospholipid (1 marks)

Answer 10

phospholipid has 1 phosphate group instead of fatty acid

Question 11

function of phosplipid (3 marks)

Answer 11

-form bilayer in cell surface membrane
-allowing diffusion of very small non-polar substances
-restricts movement of large polar molecules

Question 12

test for lipids (2 marks)

Answer 12

-add ethanol, shake and add water
-positive= milky white emulsion