enzymes🦴 Flashcards
explain the induced fit model through the breakdown of a substrate
- substrate binds to active site
- active site shape changes shape to fit to substrate more closely
- more bonds form between active site and substrate
- forms ESC
- change in shape of active site weakens bonds in substrate
- activation energy reduced
describe how an enzyme breaks down a substrate
- active site shape complementary to substrate
- active site binds to substrate
- induced fit
- forms esc
- puts strain on bonds in substrate
- forms enzyme product complex
- products leave active site
how to increase validity of an experiment testing ph effect on enzyme
- equal volume in each tube
- add buffer
how does repeating an experiment improve it
- improves reliability
- assess spread of results
- allows calculation of mean
if a molecule is a competitive inhibitor what can you conclude about its structure
- similar shape/ tertiary structure to substrate
- complementary to active site of enzyme
why are different enzymes involved at different stages of the breakdown of a large molecule
- enzymes are specific
- substrates are different shapes
- active site and substrate are complementary
- to form esc
why would enzyme activity fall to zero at ph 7
- ph much higher than optimum
- change in charge of active site
- hydrogen/ionic bonds break
- 3D shape altered
- ESC does not form
describe how to measure concentration of reducing sugar with colorimeter
- use known concentrations
- heat with benedicts solution
- use same volumes of solutions each time
- remove precipitate
- calibrate colorimeter using water
- less absorbance= more sugar
- plot absorbance against sugar concentration to get calibration curve
- use reading of unknown sugar solution and read off graph to find concentration
what is extracellular enzyme
works outside cells
how does substrate concentration affect enzyme rate
- rate increases
- more successful collisions with active site
- more ESC
- more product formation in given time
- levels off
- all active sites occupied
- enzyme working at max rate
- further increase in substrate concentration has no effect
- enzyme concentration becomes limiting factor
why does ph need to be kept constant when testing temperature effect on enzyme
- so charges in active site do not change
- so hydrogen/ionic bonds are not affected
- so active site unaltered
- so enzyme does not denature
- so substrate fits active site
- so results are valid as only one variable changed
why is there low enzyme activity below its optimum temperature
- low kinetic energy
- fewer collisions so less chance of ESC formation
- activation energy higher to reach
in competitive inhibition how does increasing substrate help
-substrate more likely to collide with active site than inhibitor
how would a more flexible structure allow enzyme to work at a low temperature
-easier for active site to change shape as part of induced fit
if 2 organisms have the same enzyme with a different structure how might their dna differ
- different base sequence
- different proportion of bases
- different gene would code for polypeptide
