What you’ll learn8 learning objectivesChoose one objective for a focused lesson, or study the complete topic.7.4.1Chemical digestion as the breakdown• Describe chemical digestion as the breakdown of large insoluble molecules into small soluble moleculesSyllabus objective7.4.2Role of chemical digestion• State the role of chemical digestion in producing small soluble molecules that can be absorbedSyllabus objective7.4.3Functions of enzymes as follows: (a)• 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 glycerolSyllabus objective7.4.4Where, in the digestive system• State where, in the digestive system, amylase, protease and lipase are secreted and where they actSyllabus objective7.4.5Functions of hydrochloric acid• Describe the functions of hydrochloric acid in gastric juice, limited to killing harmful microorganisms in food and providing an acidic pH for optimum enzyme activitySyllabus objective7.4.6Digestion of starch in the digestive• 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 intestineSyllabus objective7.4.7Digestion of protein by proteases• 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 intestineSyllabus objective7.4.8Bile is an alkaline mixture that• 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 actionSyllabus objective