HWrkSht 1_13
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This Homework requires you to complete a graph on the GRAPH PAPER in your jotter. Use only a half page of graph paper for each graph. You should complete the graph on the graph sheet opposite the written answers.
1. The following investigation was set up to examine the effects of stirring on the digestion of protein.
Each piece of protein was weighed every two hours.
The results are shown in the table.
a) Use the data in the table to draw a line graph
b) Which type of enzyme would produce the results shown?
c) When the protein was completely digested, no solid material remained in the tube. Explain why.
d) Name one factor, not already mentioned, which would need to be the same in each tube at the start of the investigation.
e) Suggest how the investigation could be improved to provide a more reliable measurement of the difference which stirring made.
f) Stirring increased the rate at which the protein was digested. Explain why this happened.
2. The enzyme amylase breaks down starch to maltose. An investigation was carried out to see how this reaction was affected by pH.
Nine test-tubes were set up with the contents as shown in the diagram. Each contained a different buffer solution which controlled the pH.
The contents of the tubes were monitored to see what percentage of starch had been converted to maltose in 20 minutes.
The results are shown in the table below.
a) Plot a line graph of the data.
b) Give all pH values used in this investigation at which the enzyme was found to be inactive.
c) Describe the effect of increasing pH, from pH 3 to pH 10, on the activity of amylase.
d) Name one factor, other than pH, which can affect the activity of an enzyme.
3. Enzymes are described as “biological catalysts”.
a) What is the meaning of the term “catalyst”?
b) Name an enzyme involved in a synthesis reaction.
