ENZYMES Flashcards
what are enzymes?
biological catalysts that speed up a reaction by reducing the activation energy and remain unchanged at the end of a reaction
what are anabolic and catabolic reactions
anabolic: building up
catabolic: breaking down
what type of proteins are enzymes?
globular proteins
why are enzymes specific?
because the shape of the active site allows only one substrate ind temporarily forming the enzyme-substrate complex
what is the lock and key fit theory?
suggests that the enzyme has a specific shape that can only allow one type of substrate to enter. when a substrate temporarily binds to the enzyme it forms an enzyme-substrate complex. the enzyme finishes the reaction and the product leaves and the enzyme can be reused.
what is the induced fit theory?
suggests that when the substrate binds to the enzyme, the enzyme changes it’s shape to make the substrate fit perfectly on the active site
how does temperature affect rate of reaction?
at low temperatures, particles move slowly so substrate will not collide with the enzyme
as temperature rises, particles gain more energy and move faster causing more frequent collisions
when the optimum temperature is reached that is the maximum rate
above the optimum temperature will cause the enzyme to denature
how does pH affect the rate of reaction?
each enzyme has a different optimum pH
below of above the optimum pH will cause the enzyme to denature
how does substrate concentration affect rate of reaction?
an increase in substrate equals an increase in the rate of reaction as there is more substrate binding to the enzymes however, when all enzymes are working the rate will start to plateau
how does enzyme concentration affect rate of reaction?
the more enzymes present the more reactions will occur so as long as there is enough substrate the rate will increase until the point where there is no substrate left and it will start to plateau
what are protein inhibitors?
a substance that prevents substrates from binding onto to active site. they’re either competitive or non competitive
what does a competitive inhibitor do?
it has a similar shape to the substrate and it fits into the active site and occupies it blocking any other substrate to enter which reduces the formation of the product.
when substrate increases the inhibitor leaves the enzyme and the rate starts to increase
this type of inhibition is reversible
what does a non competitive inhibitor do?
they bind to the allosteric site which disrupts the bonds inside the enzyme changing its overall shape which causes a change in the shape of the active site which makes the substrate unable to fit.
this type of inhibition is irreversible
