B2.1.4d) To explain the factors affecting enzymes rate of reaction

Question 1

Turnover number

Answer 1

Number of substrate molecules transformed per minute by 1 enzyme molecule

Question 2

Measuring effect of an enzyme

Answer 2

Enzyme + Substrate (loss of the substrate in an amount of time) → Product (product make in amount of time)
Compare uncatalysed rate with catalysed rate
Enzymes can increase rate by a factor of between x10^8 to x10^26

Question 3

Increasing substrate concentration

Answer 3

High collision rate with the enzymes active site
More ESCs form
More product produced in a given time
Higher rate of reaction

Question 4

Why measure initial rate of reaction?

Answer 4

Before any factors have had time to change
Rate of enzymes- catalysed reactions are affected by temperature

Question 5

Q10 Temperature coefficient

Answer 5

Q10= rate of reaction at (x+10)℃ / rate of reaction at x℃

Question 6

pH affect on the rate of reaction

Answer 6

pH affects the formation of hydrogen & disulphide bonds in proteins so it affects the shape
Changing pH- changing the concentration of H+ ions of the environment
Interferes with H & ionic bonds- hold active site in specific shape

Question 7

Increasing enzyme concenttration

Answer 7

With increasing substrate concentration
Adding more active sites- increase number of ESCc, which can form in a given time- speeds up rate of reaction
* upto a point
More actives sites than substrate
Substrate concentration will limit rate of reaction