Explain that bile is an alkaline mixture that neutralises the acidic mixture of food and gastric juices entering the duodenum from the stomach, to provide a suitable pH for enzyme action

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Describe the digestion of protein by proteases in the digestive system: (a) pepsin breaks down protein in the acidic conditions of the stomach (b) trypsin breaks down protein in the alkaline conditions of the small intestine

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Describe the digestion of starch in the digestive system: (a) amylase breaks down starch to maltose (b) maltase breaks down maltose to glucose on the membranes of the epithelium lining the small intestine

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Describe the functions of hydrochloric acid in gastric juice, limited to killing harmful microorganisms in food and providing an acidic pH for optimum enzyme activity

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State where, in the digestive system, amylase, protease and lipase are secreted and where they act

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Describe the functions of enzymes as follows: (a) amylase breaks down starch to simple reducing sugars (b) proteases break down protein to amino acids (c) lipase breaks down fats and oils to fatty acids and glycerol

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State the role of chemical digestion in producing small soluble molecules that can be absorbed

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Describe chemical digestion as the breakdown of large insoluble molecules into small soluble molecules

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Outline the role of bile in emulsifying fats and oils to increase the surface area for chemical digestion

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Describe the function of the stomach in physical digestion

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