Enymes Flashcards
Active site definition:
The part of an enzyme to which the substrate binds forming an enzyme substrate complex.
Enzyme substrate complex definition:
These occur as a result of successful collisions between an enzymes active site and a substrate.
Kinetic energy definition:
This movement energy increases with temperature making a higher chance of successful collisions.
Successful collisions definition:
Collision between enzymes active site and substrate to form enzyme substrate complexes.
Complementary shape definition:
Relationship between the shape of the enzymes active site and the substrate.
Tertiary structure definition:
Determines the shape of the enzymes active site.
Tertiary structure definition:
Determines the shape of the enzymes active site.
Specific shape definition:
The shape of an active site is specific to one particular substrate.
Enzyme definiton:
Biological catalyst made up of proteins.
Enzyme definiton:
Biological catalyst made up of proteins.
How do enzymes act as a biological catalyst?
Enzymes lower the activation energy making reactions happen faster, speeding up the rate of reaction.
The lock and key model of an enzyme:
The substrate fits into the enzyme the way a key fits into a lock.
The induced fit model of an enzyme:
The substrate is not initially complementary to the enzymes active site. Instead the active site changes shape becoming complementary as it moulds around the substrate. This puts pressure on the of the substrate, bending them and making them more likely to break. This lowers the activation energy.
The effect of temperature of enzyme activity ( describe ) :
- as temperature increases, rate of reaction increases
- hits optimum temperature ( include data )
- as temperature continues to increase, rate of reaction decreases
The effect of temperature on enzyme activity ( explain ) :
- as temperature increases, the molecules have more kinetic energy, more successful collisions so more enzyme substrate complexes
- hits optimum temperature ( include data )
- denature of enzymes, breaking hydrogen and ionic bonds in tertiary structure, changes tertiary structure
- active site is no longer complementary to substrates, fewer enzymes substrate complexes formed
The effect of pH on enzyme activity ( describe ) :
- as pH increases, rate of reaction increases
- hits optimum pH ( include data )
- as pH continues to increase, rate of reaction decreases
The effect of pH on enzyme activity ( explain ) :
- high concentration of protons ( H+ )at low pH, these breaks hydrogen and ionic bonds
- tertiary structure changes shape so active site is no longer complementary to the substrate so fewer enzyme substrate complexes formed
- hits optimum pH ( included data )
- increase in pH from optimum increases hydroxyl ion concentration ( OH-), these break hydrogen and ionic bonds so tertiary structure changes, rate of reaction decreases
The effect of substrate concentration on enzyme activity ( describe ) :
- as substrate concentration increases the initial rate of reaction increases
- the rate plates as substrate concentration continues to increase
- ( include date )
The effect of substrate concentration on enzyme activity ( explain ) :
- initially there is an increase in rate of reaction as more enzyme - substrate complexes are formed as substrate concentration increases
- the platoeing of the reaction occurs as the enzyme active sites are full/ saturated, this limits the rate of reaction
The effect of enzyme concentration on enzyme activity ( describe ) :
- as enzyme concentration increases, rate of reaction increases
The effect of enzyme concentration on enzyme activity ( explain ) :
- as enzyme concentration increases, rate of reaction increases as more enzyme substrate complexes form
- the concentration of enzymes doesn’t exceed the concentration of subsrate so it doesn’t plato
Competitive inhibitor:
- the competitive inhibitor and substrate have a similar shape
- they compete to bind to the enzymes active site so fewer enzyme substrate complexes form
- they are both complementary to the active site
Non - competitive inhibitor:
- binds to the enzyme away from its active site
- this changes the shape of the enzymes active site meaning it is so longer complementary to the subrate
- fewer enzyme substrate complexes form
The effect of substrate concentration on enzyme activity with a competitive inhibitor:
- increasing the substrate concentration increases the rate of reaction until the rate becomes the same as the normal enzyme without inhibitor
- this is because the substrate has outcompeted the inhibitor for the enzymes active sites
The fact of subsrate concentration on enzyme activity with a non - competitive inhibitor:
- increasing the substrate concentration in a reaction with a non - competitive inhibitor has no effect as the enzymes active sites are no longer complementary
- no enzyme - substrate complexes can form
