Biological Molecules Flashcards
(33 cards)
how are polymers formed
monomers join a chemical bond by a condensation reaction which releases a molecule of water
how are polymers broken down
hydrolysis, water is used to break down the chemical bond.
monosaccharides: what type of sugar is glucose and what are its isomers
a hexose sugar, it has 6 carbon atoms in each molecule. alpha and beta glucose. alpha has the OH at the bottom and H at the top
disaccharies: how are they formed and what bond is created
monosaccharides form a glycosidic bond by a condensation reaction and
what monosaccharides form sucrose, lactose and maltose
sucrose = glucose+fructose lactose = glucose+galactose maltose = 2x alpha glucose
what is the reducing sugar test
eg all monosaccharides + lactose, maltose. Add blue benedict’s reagent, boil in water bath, change in colour = reducing sugar. green - yellow - brick red.
what is the non reducing sugar test
eg sucrose. add benedict’s reagent, hydrochloric acid and boil in a water bath. neutralise with sodium hydrocarbonate. add benedicts reagent again. blue = non-reducing sugar. this method can be used to get a reducing sugar out of a non-reducing sugar solution.
why use a colorimeter when using benedict’s test
to test the concentration of precipitate. it does this by absorbing the remaining benedict’s reagent
what is starch used for in plants
the alpha glucose polysaccharide is broken down by hydrolysis to make amylose and amylopectin to use for energy
what is amylose used for
long, unbranched, coiled, compact, great for storage
what is amylopectin use for
long, branched so enzymes break glycosidic bonds easily = easy glucose release
what is good about starch
insoluble in water so doesn’t affect water potential which makes it good for storage
what is the structure and function of gylcogen
excess glucose turns into glycogen. many branches of alpha glucose, compact and quick release of energy for mammals
cellulose structure and function
long, unbranched, beta-glucose chains. cellulose chains joined by hydrogen bonds which form strong fibres called microfibrils = support in plant cell walls
iodine test for starch
add iodine, blue/black = starch. brown/orange = no starch
lipids: structure of triglycerides
one molecule of glycerol and 3 fatty acid molecules (a tail) called hydrocarbons. tail in hydrophobic, so insoluble in water. ester bonds formed between FA and glycerol by condensation reaction
difference between un/saturated fatty acid
un = have double bonds between carbon atoms sat = no double C bonds, is saturated with Hydrogen
structure of a fatty acid
O = C - HO - R(variable hydrocarbon tail)
structure of a phospholipid
found in cell membrane, 2 FA , 1 glycerol, 1 phosphate group (hydrophilic)
properties of lipids
triglycerides = storage, insoluble, don't affect water potential phospholipids = bilayer of cell membrane, not easy for water soluble molecules to pass through the hydrophobic centre layer
emulsion test for lipids
shake sample with ethanol, pour into water, lipid shows as a milky emulsion above the water
what are proteins made from
amino acids, 2x a.a = dipeptide 2+x a.a = polypeptide
structure of a amino acids
carboxcylic acid, r group, amine group. theres only 20 amino acids, their r groups is the only difference
how are di/polypeptides formed
condensation reaction forms a dipeptide bond. hydrolysis breaks this down
