IB›IB Biology HL›Mind mapsC1.1 Enzymes and metabolismIB Biology HL: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsMetabolismAnabolism builds macromolecules by condensationCatabolism breaks down by hydrolysis or oxidationIntracellular: glycolysis; extracellular: gut digestionInefficiency releases heatHow they workGlobular proteins with a specific active siteInduced fit: enzyme and substrate change shapeEnzymes lower activation energyDenaturation changes the active siteRate factorsRate rises with temperature up to the optimumEach enzyme has an optimum pHMore substrate until saturationRate = product ÷ time, or 1/timeEnzymescatalysts of metabolismEaInhibitionCompetitive: binds active site, overcome by substrateNon-competitive: binds allosteric site, changes shapeStatins competitively inhibit HMG-CoA reductasePathway controlFeedback inhibition: end product blocks early enzymeIsoleucine inhibits threonine deaminasePenicillin irreversibly blocks transpeptidasesResistance: modified transpeptidaseExam tipsExtra substrate cancels competitive inhibition onlyPenicillin is irreversible, not competitive