IB›IB Biology SL›Mind mapsA1.1 WaterIB Biology SL: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsMedium for lifeFirst cells originated in waterCytoplasm is mostly waterEnzymes work in aqueous solutionBlood plasma, xylem and phloem sap carry solutesPolarityOxygen pulls shared electrons: unequal sharingO is δ−, each H is δ+Hydrogen bond: δ+ H of one molecule to δ− O of the nextOne bond is weak, huge numbers add upCohesion, adhesionCohesion: water to waterAdhesion: water to polar or charged materialCohesion keeps the xylem column continuous under tensionSurface tension lets pond skaters live on the surfaceCapillary action needs both, e.g. in soilWaterthe medium for lifeH₂Oδ+δ−SolventHydrophilic: polar or charged, dissolvesHydrophobic: non-polar, insolubleInsoluble tails form the membrane coreCholesterol travels inside lipoproteinsWater vs airBuoyancy: water about 800 times denser than airViscosity: more drag, so streamlined bodiesThermal conductivity 20–25 times air: insulation neededHigh specific heat capacity: stable temperaturesExam tipsHydrogen bonds are between molecules, not withinCohesion = water to water, adhesion = water to otherDraw hydrogen bonds as dashed lines, label δ+ and δ−Common or scientific organism names both accepted