Questions and Answers

Understand that the different proteases present in the stomach and the duodenum work best at different pH levels

Describe the function of hydrochloric acid in the stomach as killing ingested bacteria

Describe the functions of amylase, maltase, protease and lipase, listing the substrates and endproducts, limited to: (a) amylase breaks down starch to maltose (b) maltase breaks down maltose to glucose (c) protease (pepsin and trypsin) breaks down protein to amino acids (d) lipase breaks down lipids to fatty acids and glycerol

State that physical digestion increases the surface area of food for the action of enzymes in chemical digestion

Explain why most foods must be digested before they can be absorbed

Understand the concept of a balanced diet

Name the diseases and describe the symptoms resulting from deficiencies of vitamin C (scurvy), vitamin D (rickets), calcium (rickets) and iron (anaemia)

List the principal sources of, and describe the dietary importance of, carbohydrates, lipids, proteins, vitamins (C and D only), mineral salts (calcium and iron only), fibre (roughage) and water

Relate the structure of xylem vessels to their function, limited to: (a) thick walls with lignin (details of lignification are not required) (b) no cell contents (c) cells joined end-to-end with no cross walls to form a long continuous tube

State the functions of xylem as transport of water and mineral ions, and support