IGCSE Biology

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

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

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

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

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

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

Describe the function of the stomach in physical digestion

Identify in diagrams and images the types of human teeth: incisors, canines, premolars and molars

Describe physical digestion as the breakdown of food into smaller pieces without chemical change to the food molecules

Describe the functions of the organs of the digestive system in relation to: (a) ingestion – the taking of substances, e.g. food and drink, into the body (b) digestion – the breakdown of food (c) absorption – the movement of nutrients from the intestines into the blood (d) assimilation – uptake and use of nutrients … Read more