IB›IB Biology SL›Mind mapsB1.2 ProteinsIB Biology SL: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsAmino acidCentral alpha carbon with four groupsAmine –NH₂ and carboxyl –COOHA hydrogen atomR-group is the only variable partMaking chainsCondensation forms a peptide bond, releases waterAmino acid + amino acid → dipeptide + waterChain of n has n − 1 peptide bondsHydrolysis reverses it, using waterDietEssential: cannot be made, must be eatenNon-essential: made from other amino acidsPlant proteins low in some essentialsMix cereals with legumes on a vegan dietProteinsamino acids to shape–NH₂–COOHREndless varietyCode specifies 20 amino acidsAny order, any length: 20n20^n20n sequencesA 9-chain has 5.12×10115.12 \times 10^{11}5.12×1011 optionsInsulin 51, oxytocin 9, titin about 34 000DenaturationFunction depends on 3D shapeHeat breaks weak bonds by vibrationExtreme pH changes charges and disrupts bondsShape change is permanent, function lostSoluble proteins often clumpExam tipsCount peptide bonds, not amino acids, for waterDenaturation keeps the sequence, peptide bonds intactNo need to name essential amino acids