LIPIDS

Question 1

lipid properties

Answer 1

contains carbon hydrogen and oxygen
less oxygen in proportion to carbohydrates
insoluble in water
soluble in alcohols and acetone
main groups are triglycerides and phospholipids

Question 2

example of triglyceride

Answer 2

fats/oils

Question 3

example of phospholipid

Answer 3

cell membrane

Question 4

roles of lipids in the body

Answer 4

source of energy- when oxidized, provide twice the amount of energy than carbohydrates
waterproofing-insoluble in water. mammals secrete oily substances from skin, plants have waxy cuticle
insulation- slow conductor of heat so help bodies retain heat. used in electrical insulation as myelin sheath around nerve cells
protection- stored around delicate organs like the liver (fatty layer)

Question 5

chemical structure of lipids

Answer 5

do not form polymers
big molecules made of smaller subunits
not a continuing chain

Question 6

triglycerides

Answer 6

have 3 fatty acids combined with a glycerol
via a condensation reaction
forming an ester bond

Question 7

fats

Answer 7

saturated fatty acids
no double bonds
solid at room temp

Question 8

oils

Answer 8

unsaturated fatty acids
have double bonds
liquid at room temp

Question 9

how does the structure of triglycerides relate to its function

Answer 9

high C:H bonds-excellent source of energy
low mass: energy -good storage molecules
large non polar molecules-insoluble in water
high ratio of H:O atoms-triglycerides release water when metabolised providing source of water for desert animals

Question 10

how does phospholipids structure relate to its function

Answer 10

found within the cell surface membrane as a bilayer
can form glycolipids to aid in cell recognition by combining with carbohydrates
phosphate molecules attract water (hydrophilic) therefore a phospholipid has a hydrophilic head
fatty acid molecules repel water (hydrophobic) therefore a phospholipid has a hydrophobic tail
phosphate molecule replaces a fatty acid from a triglyceride