Student extension B3 - Kerboodle

1 Student extension Name .. Class .. Date .. Oxford University Press 2016 This resource sheet may have been changed from the original. 1 The effect of pH on enzyme action Specification references The human digestive system WS , , , , , , , , , Aims The aim of this task is for you to design an experiment to investigate enzyme action. The detail that you will include in the design will push you towards the level required for sixth form studies in biology. Learning outcomes After completing this worksheet, you should be able to: construct a reasoned hypothesis to predict the outcome of an investigation write a full design for an experimental investigation explain how to manipulate and control variables explain how to process data to reach a conclusion. Setting the scene A simple experiment to investigate the action of an enzyme uses cellulase to digest wallpaper paste.

2 The experiment works by mixing the cellulase with viscous wallpaper paste and pouring the mixture through a funnel or syringe barrel. The time taken to drain through is recorded and the process is repeated until the time taken stabilises. The experiment works because the cellulase digests the viscous wallpaper paste and causes it to become runnier. Your teacher may show you a basic method to demonstrate this, listing the equipment required and including an example of a calculation to work out relative cellulase activity. Task Write a full design for an investigation into the effect of pH on the action of cellulose, an enzyme. Start by researching the action of the enzyme cellulase so that you are able to explain clearly how it works and predict the factors that may affect its action. Next, research the factors that affect the speed of enzyme action so that you are able to anticipate the relevant controls and decide how to manipulate the independent variable.

3 Student extension Name .. Class .. Date .. Oxford University Press 2016 This resource sheet may have been changed from the original. 2 Your design should include: an introductory section explaining the relevant scientific background and setting up a reasoned prediction a clear method including a full equipment list, explanation of how the independent variable is to be controlled, explanation of how control variables will be managed, and explanation of how the dependent variable will be measured an explanation of the possible uncertainties that may occur in your measurements, such as unavoidable timing errors due to reaction times or measurement uncertainties due to precision of equipment ( , it is only possible to measure mm with a mm scale ruler) a safety risk assessment an indication of how the data will be processed to give a conclusion, including suggested mathematical analysis that could be done a bibliography listing the sources you have consulted.

4 Student follow-up Having designed the method, why not carry out the actual investigation? You could consider building this into a larger-scale investigation for a CREST Award project.