Enymes

Question 1

Active site definition:

Answer 1

The part of an enzyme to which the substrate binds forming an enzyme substrate complex.

Question 2

Enzyme substrate complex definition:

Answer 2

These occur as a result of successful collisions between an enzymes active site and a substrate.

Question 3

Kinetic energy definition:

Answer 3

This movement energy increases with temperature making a higher chance of successful collisions.

Question 4

Successful collisions definition:

Answer 4

Collision between enzymes active site and substrate to form enzyme substrate complexes.

Question 5

Complementary shape definition:

Answer 5

Relationship between the shape of the enzymes active site and the substrate.

Question 6

Tertiary structure definition:

Answer 6

Determines the shape of the enzymes active site.

Question 7

Tertiary structure definition:

Answer 7

Determines the shape of the enzymes active site.

Question 8

Specific shape definition:

Answer 8

The shape of an active site is specific to one particular substrate.

Question 9

Enzyme definiton:

Answer 9

Biological catalyst made up of proteins.

Question 10

Enzyme definiton:

Answer 10

Biological catalyst made up of proteins.

Question 11

How do enzymes act as a biological catalyst?

Answer 11

Enzymes lower the activation energy making reactions happen faster, speeding up the rate of reaction.

Question 12

The lock and key model of an enzyme:

Answer 12

The substrate fits into the enzyme the way a key fits into a lock.

Question 13

The induced fit model of an enzyme:

Answer 13

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.

Question 14

The effect of temperature of enzyme activity ( describe ) :

Answer 14

• as temperature increases, rate of reaction increases
• hits optimum temperature ( include data )
• as temperature continues to increase, rate of reaction decreases

Question 15

The effect of temperature on enzyme activity ( explain ) :

Answer 15

• 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

Question 16

The effect of pH on enzyme activity ( describe ) :

Answer 16

• as pH increases, rate of reaction increases
• hits optimum pH ( include data )
• as pH continues to increase, rate of reaction decreases

Question 17

The effect of pH on enzyme activity ( explain ) :

Answer 17

• 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

Question 18

The effect of substrate concentration on enzyme activity ( describe ) :

Answer 18

• as substrate concentration increases the initial rate of reaction increases
• the rate plates as substrate concentration continues to increase
• ( include date )

Question 19

The effect of substrate concentration on enzyme activity ( explain ) :

Answer 19

• 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

Question 20

The effect of enzyme concentration on enzyme activity ( describe ) :

Answer 20

• as enzyme concentration increases, rate of reaction increases

Question 21

The effect of enzyme concentration on enzyme activity ( explain ) :

Answer 21

• 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

Question 22

Competitive inhibitor:

Answer 22

• 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

Question 23

Non - competitive inhibitor:

Answer 23

• 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

Question 24

The effect of substrate concentration on enzyme activity with a competitive inhibitor:

Answer 24

• 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

Question 25

The fact of subsrate concentration on enzyme activity with a non - competitive inhibitor:

Answer 25

• 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