Required practicals

Question 1

1 investigation into effect of a named variable on the rate of an enzyme controlled reaction

give 5 examples of variables that could affect the rate of enzyme

Answer 1

• enzyme conc.
• substrate conc.
• temp. of solution
• pH of solution
• inhibitor conc.

Question 2

RP1 (effect of variable on enzyme controlled reaction)

• describe how temperature can be controlled
• describe how pH can be controlled
• why were the enzymes and substrate solutions left in water bath for 10 min b4 mixing
• describe a control experiment

Answer 2

• use a thermostatically controlled water bath, monitor using thermometer at regular intervals and add hot/cold water is temp fluctuates

0 use a buffer solution, monitor using pH meter at reg. intervals

• solutions equilibrate and reach temp of water bath
• use denatured enxymes e.g. by boiling and keep everything else the same e.g. volume and conc. of substrate, enzyme type, volume and type of buffer solution and temp

Question 3

RP1

describe how the rate of an enzyme controlled reaction can be measured

Answer 3

• measure time taken for reaction to reach a set point e.g. conc, volume, mass, colour of substrate or product
• rate of reaction = 1/time
  measure conc, volume, mass, colour at reg intervals throughout the reaction
• plot graph time x, measuring y
• tangent at t=0 or any other time for rate at particular point
• initial rate of reaction = change in y/change in x