enzymes Flashcards
enzymes are biological
catalysts
a catalyst is a ……..
chemical which increases the rate of a reaction without being used up itself in the reaction
the theory for understanding how enzymes work is the
lock and key theory
what is the lock and key theory
the substrate and enzyme collide,
the substrate binds to the active site of the enzyme,
(the reaction occurs by an alternative pathway with a lower activation energy)
once the reaction occurs, the products don’t fit - so they are released,
the enzyme is free to catalyse the next reaction
the active site has a particular shape which is … to the shape of the substrates
complementary
because the shape of the AS is complementary to that of the substrates, this means
each enzyme can only catalyse one reaction
as temperature increases the enzyme & substrate have more
kinetic energy
so they move faster and there are more successful collisions
high temperatures and changes of pH cause the shape
to change
when the shape changes we say this is
the protein being denatured
when the active site changes shape it is no longer
complementary to the substrate
examples of increasing the concentration
adding more substrate or enzyme
increasing the concentration will
speed up the reaction
