UNIT 2: key area 1 c) enzymes in metabolic pathways Flashcards
explain enzyme function in terms of the induced fit model
induced fit - when the active site of an enzyme changes shape to better fit the substrate after it binds
state the affinities of an enzyme for the product and substrate
the active site has a high affinity to substrate and is substrate specific
this allows the reactant into the correct position for reaction to take place
as products are made they are no longer specific to the active site and are therefore released
describe enzyme activity in terms of substrate and enzyme concentrations
as substrate concentration increases, the enzyme reaction increases untill all active sites are occupied
when all are occupied enzyme is saturated - adding more substrate to saturation point makes no difference
descirbe the action of competitive and non-competitive inhibition
competitive bind at the active site stopping at he substrate from binding whereas non competitive bind away from the active site and change shop stopping the active site from binding
describe feedback inhibition
feedback occurs when the end product in a metabolic pathway reaches critical concentration
explain the mechanism of feedback inhibition
occurs when the ed product in metabolic pathway reaches critical condition
why is feedback inhibiton important important
end product inhibits an earlier enzyme preventing the synthesis of end product
what needs to happen to lower activation energy if reaction
binding of an enzyme to substrate
why does the reactant need to be in correct positions
for reaction to take place
if an enzyme is present what happens
amount of energy needed to make the product is lowered
what happens when products made aren’t specific to active site
they are realeased
the cell can control a metabolic pathway by the………..
presence or absence of a particular enzyme
why do metabolic pathways have to be controlled and regulated ?
to stop the build up of an end product
when does an induced fit occur ?
active site of an enzyme changes shape to better fit the substrate after it binds
the rate of enzyme reaction can be affected by what ?
substrate concentrations
as the substrate concentration increases so does what ?
the enzyme reaction increases untill all of the active sites are occupied by the substrate
when all active sites are occupied what does this mean for the enzyme ?
it is saturated
adding more substrate makes no difference to the reaction rate
what point is this
saturation point
what is enzyme inhibition
inhibitors are used to stop and enzyme from binding to substrate
what do inhibitors control
the progress of metabolic pathway
name the three types of inhibiton
competitive
non-competitive
feedback
what inhibitor can be reversed
competitive
what inhibitor can not be reversed
non-competitive
can competitive inhibition be reversed ?
True
can non-competitive inhibition be reversed ?
False
how can certain inhibitors be reversed ?
by increasing substrate concentration
