Sample Assessment

Page 1

Enzymes questions


Enzymes questions


Enzymes questions

Draw out your completed data table below


Enzymes questions

Questions 1. It is important to add the buffer to the enzyme before adding the starch. Why is this? ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ 2. Do you think your results are reliable? How would repeating the investigation help you to check the reliability? ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ 3. Explain how pH affects enzyme reactions ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ 4. Name one way in which you would improve this experiment: ___________________________________________________________________ ___________________________________________________________________


Enzymes questions

5. Plot a graph of time taken for starch to break down against pH (use your results)


Enzymes questions

6. We are able to calculate the rate of reaction by calculating 1 รท time. a. Use the space below to calculate the rate of reaction for your results.


Enzymes questions

b. Draw a graph plotting rate of reaction against pH


Enzymes questions

7. Describe your graph(s). What is the effect of pH on the enzyme controlled reaction? ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________

8. A learner investigates the effect of temperature on the activity of the enzyme catalase in potatoes. The learner follows the following method: o place a potato chip in a boiling tube and allow to stand for 10 minutes in a water bath at 2.5°C o place a boiling tube containing hydrogen peroxide in the same water bath for 10 minutes o after 10 minutes the potato chip is then added to the tube of hydrogen peroxide o a bung, with a delivery tube attached, is quickly inserted into the boiling tube. The free end of the delivery tube is placed under an inverted graduated glass tube which is filled with water. The learner repeats the steps in water baths at different temperatures. The diagram shows the setup of the equipment.


Enzymes questions

The results of the learner’s investigation are shown in the table.

The learner concludes that up to 41, a rise in temperature increases the rate of catalase activity. Above 41 the enzyme is denatured and its activity decreases. Evaluate the learner’s investigation. Your answer should include reference to: o the method of the experiment o the results collected o the conclusion made. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________


Enzymes questions

___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________


Enzymes questions

END OF EXAM


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