factors affecting enzymes

Question 1

what are the factors that affect the rate of enzyme controlled reactions ?

Answer 1

• temperature
• pH
• enzyme concentration
• substrate concentration
• inhibitors

Question 2

why are proteins sensitive to certain conditions ?

Answer 2

due to the bonds that hold them together in the tertiary structure of the protein

Question 3

draw the graph for the effect of temperature on enzymes

Answer 3

notes

Question 4

what occurs at point 1

Answer 4

molecules gain kinetic energy and collide more frequently to produce enzyme-substrate complexes more quickly
- more substrates can overcome the activation energy

Question 5

what is the peak of the graph representing ?

Answer 5

this is the optimum temperature of the enzyme

Question 6

what occurs at point 3 ?

Answer 6

enzymes denature which is irreversible

Question 7

why do enzymes denature ?

Answer 7

the high temperature causes the bonds in the tertiary structure of the active site to break and the active site changes shape so that it is not longer complementary to the substrate
- so no enzyme-substrate complexes can be formed

Question 8

draw the graph for the effect of pH

Answer 8

notes

Question 9

what happens when the conditions are too acidic ?

Answer 9

it produces too many H+ ions which bind to the R groups and interferes with hydrogen bonds and the charges in the amino acids

Question 10

what happens if the conditions are too alkaline ?

Answer 10

it produces too many OH - ions which interfere with the ionic bonds

Question 11

what do both conditions cause ?

Answer 11

they will interfere with the charges in the amino acid in the active site. which can break the bonds holding the tertiary structure in place and therefore the active site changes shape so fewer enzyme-substrate complexes form

Question 12

what do different enzyme shave in terms of pH ?

Answer 12

different enzymes have different optimal pH

Question 13

draw the graph for substrate concentration

Answer 13

notes

Question 14

what occurs at point 1 on the sc graph

Answer 14

more substrates means that more enzyme substrate complexes are produced

Question 15

what occurs at point 2 on the sc graph ?

Answer 15

substrates run out of active sites to bind to and the speed of enzyme-substrate complexes forming is stable

Question 16

draw the graph for enzyme concentration ?

Answer 16

notes

Question 17

what occurs at point 1 on the ec graph ?

Answer 17

more enzymes means that more enzyme substrate complexes are produced

Question 18

what occurs at point 2 on the ec graph ?

Answer 18

the limiting factor becomes the concentration of substrates

Question 19

what are the 2 types of enzyme inhibitors ?

Answer 19

• competitive inhibitors
• non- competitive inhibitors

Question 20

what is meant by a competitive inhibitor ?

Answer 20

competitive inhibitors are the same shape as the substrate and can bind to the active site
- this prevents the substrate from binding and the reaction to occur

Question 21

what do competitive- inhibitors do ?

Answer 21

compete for the active site

Question 22

how do you reduce the effect of the competitive inhibitor ?

Answer 22

you increase the substrate concentration
- because the higher the the substrate concentration there more likely it is that the substrate will bind to the active site and out compete the inhibitor, knocking them out of the active site

Question 23

draw the graph for the competitive inhibitor

Answer 23

notes

Question 24

what is meant by a non-competitive inhibitor ?

Answer 24

they bind to the enzyme away from the active site
- this causes the active site t change shape and therefore the substrate can no longer bind regardless of how much substrate is added

Question 25

what is the other site of the non-competitive inhibitor called ?

Answer 25

the allosteric site

Question 26

draw the graph for the non-competitive inhibitor ?

Answer 26

note

Question 27

what is meant by end product inhibition ?

Answer 27

the product made inhibits the enzyme that helped male it

Question 28

why is end product inhibition useful ?

Answer 28

because it prevents an excess of enzymes being produced in the body