This week in Body in Question’s Nutrition class, students conducted four experiments to determine how macromolecules (carbohydrates, proteins, and lipids) are chemically hydrolysed or emulsified. For each experiment, students wrote a hypothesis based on their knowledge of enzymes and the human digestive system. They tested; the effect of salivary amylase on the hydrolysis of starch, the effect of pH on pepsin activity, the effectiveness of protein and starch hydrolysis by pepsin or amylase, and simulated the effect of bile salts on the emulsification of lipids. They extrapolated their findings to the chemical digestion of food in the human gastrointestinal tract, and learnt about enzyme specificity, catalyst reactions, the induced-fit model, and optimal conditions (eg. pH, temperature) for macromolecule digestion.