1.8 Factors affecting Enzyme action

Question 1

What are the factors affecting enzyme action (5)

Answer 1

Temperature
pH
Substrate concentration
Enzyme concentration
Presence of inihibitors

Question 2

How does temperature affect enzyme action (2)

Answer 2

• If it is too low there is not enough kinetic energy for successful collisions between the enzymes and the substrate
• If it is too high enzymes denature , the active sitie changes and the ENZYME SUBSTRATE COMPLEX CANNOT FORM

Question 3

How does pH affect enzyme action

Answer 3

• If it is too high or too low the pH could interfere with the charges (+ or -) in the amino acids in the active site
• This can break the bonds holding the tertiary structure in place therefore the active site shape changes leading to fewer ENZYME SUBSTRATE COMPLEXES forming

Too high a pH= too many h+ ions
Too low a pH= too many OH- ions

Different enzymes have diff optimul pH’s

Question 4

How does the concentrations of enzymes and substrates affect enzyme action

Answer 4

• If there is insufficient substrate the reaction will be slower as there will be fewer collisions bewteen enzyme and the substrate
• If there is insufficient enzymes, the enzymes active sites will become saturated with substrates and unable to work any faster

Question 4

Describe and explain the effect of enzyme concentration on the rate of enzyme-controlled reactions (2)

Answer 4

*As enzyme conc increases, rate of reaction increases as
-Enzyme conc=limiting factor
-more enzymes so more available active sites
-so more enzyme-substrate complexes formed
*At a certain point, rate of reaction stops increasing
-substrate conc= limiting factor

Question 4

Describe and explain the effect of substrate concentration on the rate of enzyme-controlled reactions

Answer 4

-As substrate conc increases, rate of reaction increases as
*Substrate conc=limiting factor(too few enzyme molecules to occupy all active sites)
* more enzyme-substrate complexes form
-At a certain point, rate of reaction stops increasing
*Enzyme conc= limiting factor
*As all active sites saturated/occupied

Question 5

Describe and explain the effect of temperature on the rate of enzyme-controlled reactions

Answer 5

• As temp increases up to the optimum, rate of reaction increases
  -more kinetic energy
• MORE ENZYME SUBSTRATE COMPLXES form
  *However as temperature increases above the optimum temperature rate of reaction decreases
  -Enzymes denature, the tertiary strcuture and the active site of the enzyme changes shape
  -Hydrogen and ionic bonds break
  -So the active site is no longer complimentary
  -So fewer ENZYME SUBSTRATE COIMPOELXES FORM

Question 5

Describe and explain the effect of pH on the rate of enzyme-controlled reactions

Answer 5

*As pH increases/ decreases above or below t he optimum, rate of reaction decreases
-enzymes denaturing and active sites changing shape
-As hydrogen and ionic bonds break
-So active site is no longer complimnetary
-So fewer ENZYME SUBSTARTE COMPLEXES form