Required Practical 1

Question 1

What are the 4 factors that affect enzyme activity?

Answer 1

• Enzyme Concentration
• Substrate concentration
• Temperature
• pH

Question 2

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

Answer 2

Replace the enzyme solution with distilled water or boiled enzyme solution

Question 3

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

Answer 3

• Plot your results on a graph of ‘rate of reaction’ against ‘time’
• Draw a tangent at time t=0 to find the initial rate

Question 4

How is the rate of reaction calculated from time?

Answer 4

Rate of reaction= 1/time

Question 5

What of the effect of temperature on enzyme activity?

Answer 5

• As temperature increases, kinetic energy increases so more ES complexes form. The rate of reaction increases 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 6

What is the risk and level of risk associated with handling enzymes?

Answer 6

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

Question 7

Explain why buffers are used

Answer 7

To maintain the pH

Question 8

You left the test tubes in the water bath for 10 minutes before you added the enzyme to the milk powder solutions. Explain why

Answer 8

To let it heat up to the temperature

Question 9

Describe and explain what you did to make sure the temperatures of the water baths were as reliable as possible

Answer 9

Add a thermometer and check it was at a constant temperature

Question 10

Name two control variables for this experiment

Answer 10

• Temperature of water bath
• Concentration of enzyme/substrate