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7.4 Chemical digestion

Syllabus
0610–2026–2027
Topic
7.4
Level
—

7.4.1—Chemical digestion as the breakdown

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

7.4.2—Role of chemical digestion

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

7.4.3—Functions 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 glycerol

7.4.4—Where, in the digestive system

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

7.4.5—Functions 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 activity

7.4.6—Digestion 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 intestine

7.4.7—Digestion 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 intestine

7.4.8—Bile 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 action

Objective notes

8 learning objectives
ConceptIGCSE Biology