B8: Enzymes Flashcards
enzymes are..
biological catalysts
the active site is…
where chemical reactions take place
on the enzyme
define the lock and key hypothesis
active site specific to substrate
substrate fits into active site of enzyme
active site has unique 3d shape + only complementary shape substrate fits
what is specificity
only substrate with complementary shape (key)
fits into active site (lock)
enzymes convert…
substrates
into products
what is ESC
enzyme substrate complex
the enzyme isnt…
used up in the process
may be used again
hydrolysis reaction
substrate may be broken by addition of water
condensation reaction
product may be formed by removal of water
define induced fit theory
active site of enzyme specific + catalyses only one reaction
substrate with correct shape enters active site
active site slightly changes shape when substrate enters
active site fits more closely around substrate + helps reaction take place more efficiently
what are optimum conditions
enzyme works best
at specific temp + pH
why does rate of reaction decrease when conditions away from optimum
- reduction in energy available for reaction
- bonds holding enzyme in specific 3D shape broken( enzyme denatured)
what happens when enzyme denatures
shape of active site altered
so substrate no longer able to fit
active site no longer complementary to active site
what happens if temp increases
enzyme + substrate gain more kinetic energy
+ move around faster
increases chance of substrate collding with active site with sufficient energy, for reaction to occur, so rate of reaction increases
rate of reaction fastest at optimum temp
what happens above optimum temp
-enzyme begins to denature
ror begins to decrease, till it stops
when all enzymes denature
-functional shape of enzyme’s active site altered, can no longer catalyse reaction,
