Amylases are enzymes that are made in specific cells of animals and plants and also by bacteria. In humans, amylase is secreted into the alimentary canal in saliva and in pancreatic juice.

1. (a)(i)Explain what is meant by the term enzyme.[2]
2. (a)(ii)Outline two structural features of enzyme molecules. 1 2[2]
3. (a)(iii)Name both the substrate and product of amylase. substrate .................................................................................................... product ......................................................................................................[2]
4. (b)(i)Amylase produced by bacteria can be used as part of an industrial process that converts plants such as corn into biofuel. Biofuels can be used instead of diesel or petrol. The bar chart shows how the activity of amylase is affected by temperature and pH. [Figure: Bar chart showing enzyme activity at different temperatures across a range of pH values] Describe what the data in the bar chart show about the activity of the enzyme and explain why this information is useful for the producers of biofuels.[4]
5. (b)(ii)Biofuels can be burnt in vehicle engines. Suggest how biofuels can result in pollution and cause environmental change.[2]

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