10 4 Enzymes are involved in a wide range of metabolic reactions. (a) The diagram represents the structure of a maltose molecule. H HO H H OH H 6CH2OH OH H O   4 5 3 2 1 H OH H OH H 6CH2OH OH H O   4 5 3 2 1 H O Draw a diagram to show the hydrolysis of maltose. (3) 11 Turn over (b) Catalase is an enzyme found in potato cells. It catalyses the breakdown of hydrogen peroxide. hydrogen peroxide water + oxygen catalase In an investigation, cylinders of potato were cut with a cork borer. The cylinders were then sliced into discs with the same thickness and put into a small beaker containing 50 cm3 of hydrogen peroxide. The mass of the beaker and its contents was recorded over a period of 15 minutes. The graph shows the results of the experiment. 0 100 99 98 97 96 95 Mass of contents of beaker as percentage of initial mass Time / minutes 5 10 15 Explain the relationship shown in the graph. 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(c) Explain how a gene mutation can prevent the production of catalase in potato cells. 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(Total for Question 4 = 10 marks)