Practical 1

Question 1

what are the factors that affect enzyme activity?

Answer 1

1. enzyme concentration
2. substrate concentration
3. temperature
4. pH

Question 2

how is a control set up I a practical measuring enzyme activity?

Answer 2

replace enzyme solution with distilled water or boiled enzyme solution

Question 3

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

Answer 3

plot you results on a graph of ‘rate of reaction’ against ‘time’
draw a tangent at time 0 to find the initial rate

Question 4

outline the practical procedure used to measure the effect of temperature on the enzyme activity, using trypsin and milk

Answer 4

immerse equal volumes of trypsin and milk, stored in different test tubes in water bath for 5 minutes for the temperature to become constant.
mix together and immediately start timing, record the time taken for the milk to become colourless
test at least 5 temperatures with at least 3 repeats at each temperature

Question 5

how is rate of reaction calculated from time

Answer 5

rate of reaction= 1/time

Question 6

what is the effect of temperature on the 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 the 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 the 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