RP 01: Rate Of An Enzyme Controlled Reaction

Question 1

What are factors that affect enzyme activity

Answer 1

Enzyme conc

Substrate conc

Temp

pH

Question 2

How is a control set up in a practical measuring enzyme activity

Answer 2

Replace enzyme solution with distilled water or boiled enzyme solution

Question 3

How can results of practical measuring enzyme activity be used to find initial reaction rate

Answer 3

Plot your results on a graph of ‘rate or reaction’ against ‘time’

Draw tangent at time=0 to find initial rate

Question 4

Outline practical procedure used to measure effect of temp on enzyme activity, using trypsin and milk

Answer 4

Immerse equal vol of trypsin and milk, stored in diff test tubes, in a water-bath for 5 mins for temp to equilibrate

Mix together + immediately start timing, record time taken for milk to be completely hydrolysed (become colourless/same as control standard set up)

Test at least 5 temps, with at least 3 repeats at each temp

Question 5

How rate of reaction calculated from time

Answer 5

Reaction rate = 1 / time

Question 6

What is effect of temp on enzyme activity

Answer 6

As temperature increases, kinetic energy increases so more ES complexes form. The rate of reaction increases up to the optimum temperature.

Beyond that, bonds in the enzyme tertiary structure break, which changes the shape of the active site. The substrate and enzyme are no longer complementary, so rate of reaction decreases.

Question 7

What is risk and level of risk associated with handling enzymes

Answer 7

Students may have allergic reactions to enzymes, so avoid contact with skin and eyes, wear eye protection.

Low risk