Protein and enzymes Flashcards
draw the structure of an amino acid
-amine group
-r group
-carboxylic acid group
-hydrogen
dipeptide
-two amino acids joined
-via a condensation reaction
-joined by a peptide bond
primary structure
-the order/number/sequence of amino acids
secondary structure
-the way the chain is folded into
-beta pleated cheated
-alpha helical
-held together by hydrogen bonding
tertiary structure
-further folding into complex 3D specific structure held together by bonds between R-groups of different amino acids
-HYDROGEN between HO
-IONIC between +/- R groups
-DISULPHIDE bridges
-makes the protein specific to its structure
quaternary structure
-two or more polypeptide chains
test for proteins
-place sample in a test tube
-add equal volumes of Biuret solution
-colour change to purple shows protein is present
Enzyme action and definition
-enzymes are globular proteins which act as biological catalysts
-increase the rate of reaction
-lowering the activation energy
-done by stressing the bonds during the formation of the ESC
lock & key model
-active site is rigid and does not change shape
-substrate binds to enzymes active site
-substrate fits exactly to the complementary active site
-products are formed so are released as no longer fit the active site
-enzyme free to take part in another reaction
induced fit model
-active site not complementary
-active site changes shape as the substrate binds
-so stressed the substrate bonds to lower the Ea of the reaction
-active site returns to its original shape
effect of temperature on ROR
-increase in temp
-increase in kinetic energy
-more successful collisions
- more ESC form per second
-denaturation: past the optimum the hydrogen/ionic bonds will break causing a change in tertiary structure causing a change in the active site
-active site is no longer complementary so less ESC
effect of pH
-enzymes have an optimal pH
-if made more acidic or more basic
-charge on R groups are changed
-ionic bonds are broken
-tertiary structure is changed
-active site changes shape
-no longer complementary
-less ESC formed
effect of substrate conc. on graph
-increases
-plateaus
-as enzyme becomes the limiting factor
effect of enzyme conc. on graph
-increases
-plateaus
-as substrate becomes the limiting factor
competitive inhibitors
-similar shape to substrate
-binds to active site
-less ESC
-less product formed
