GCSE›AQA GCSE Biology›Mind mapsDigestive System and EnzymesAQA GCSE Biology: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsEnzymesTurn large insoluble molecules into small soluble onesCarbohydrase (amylase): carbohydrates → simple sugarsProtease: proteins → amino acidsLipase: lipids → glycerol and fatty acidsWhere madeAmylase: salivary glands, pancreas, small intestineProtease: stomach (pepsin), pancreas, small intestineLipase: pancreas and small intestineBileMade in the liver, stored in the gall bladderAlkaline: neutralises stomach acidGives enzymes their optimum pHEmulsifies fat into small dropletsBigger surface area speeds up lipaseDigestionenzymes and bileamylaseFood testsBenedict's: sugar, blue → brick-red on heatingIodine: starch, orange-brown → blue-blackBiuret: protein, blue → purplepH practicalMix amylase, starch and a bufferSample into iodine at regular intervalsIodine stays orange-brown when starch is goneRate = 1÷time1 \div \text{time}1÷timeWater bath keeps temperature constantExam tipsBile is not an enzymeIt increases fat's surface area, not chemical breakdownName a specific organ for where an enzyme acts