factors that affect enzyme action

Question 1

name the 4 factors that affect enzyme action

Answer 1

high temperatures
too low or high pH
substrate concentration
enzyme concentration

Question 2

explain what an increase in temperature (below optimum) does to the rate of reaction

Answer 2

increase in temperature
molecules (substrate and enzymes) have more kinetic energy
therefore, there are more collisions between the enzyme and substrate so there are more enzyme substrate complexes being formed so there is an increased rate of reaction

Question 3

explain what an increase in temperature above the optimum temperature does to the rate of reaction

Answer 3

above optimum temperature a further increase in temperature causes the enzymes to vibrate which then causes the hydrogen and ionic bonds in the tertiary structure the protein to break. So, the shape of the active site is changed therefore the substrate’s shape is no longer complimentary to the active site so no enzyme substrate complexes can form so there is a decreased rate of reaction as the enzyme is denatured

Question 4

explain what an increase/decrease in pH does to the rate of reaction

Answer 4

above and below an enzyme’s optimum pH the H+ ions in acids and the OH- ions in alkalis affect the hydrogen and ionic bonds in the tertiary structure of the enzymes

this is because it changes the shape of the enzymes active site
- shape of the active site is longer complementary to the substrate
- fewer/no enzyme substrate complexes can form therefore there is a decreased rate of reaction, so the enzyme is denatured

Question 5

explain what an increase in enzyme concentration has on rate of reaction

Answer 5

increased number of enzymes present
increased number of active sites
increased number of enzyme-substrate complexes
increased rate of reaction

but
as you carry on increasing enzyme concentration it has no effect on rate of reaction due to substrate concentration being the limiting factor

Question 6

explain what an increase in substrate concentration has on rate of reaction

Answer 6

there are more substrates present so rate of reaction increases as more enzyme-substrate complexes can be formed

but
as you carry on increasing substrate concentration it does not affect the rate of reaction due to enzyme concentration being the limiting factor

Question 7

define enzyme inhibtors

Answer 7

a molecule that binds to an enzyme and stops it from functioning by stopping es complexes from being formed

Question 8

what are the 2 groups of enzyme inhibitors

Answer 8

competitive inhibitors
non competitive inhibitors

Question 9

what are competitive inhibitors

Answer 9

molecules that compete the the active site and have similar shape to the substrate

Question 10

what are non competitive inhibitors

Answer 10

molecules that bind to the enzyme away from the active site, this causes the active site to change shape so the substrate no longer able to bind to active site so the enzyme is no longer functional

Question 11

explain competitive inhibitors’ impact on the rate of reaction if substrate concentration is increased

Answer 11

with a competitive inhibitor substrate concentration increases the rate of reaction increases because there is an increased chance of the substrate molecule successfully colliding with the active site of the enzyme. so the number of enzyme substrate complexes increases therefore so does the rate of reaction

Question 12

explain the relationship between non competitive inhibitors and rate of reaction vs substrate concentration

Answer 12

increase in substrate concentration doesn’t result in an increased rate of reaction

Question 13

how do non competitive inhibitors prevent es complexes forming

Answer 13

non-competitive inhibitors binds to a site that is not the active site
this changes the shape of the active site and prevents es complexes from forming