Polarity creates hydrogen bonding
Polarity creates hydrogen bonding

Water is a major component of cytoplasm, blood plasma, tissue fluid, and plant sap, so many biological reactions happen in an aqueous environment. Its biological importance starts with structure: in each H2OH_2OH2O molecule, oxygen attracts the shared electrons more strongly than hydrogen does.
Step-by-step lessons on AQA A Level Biology Water, covering Water. Each one builds up to exam-style questions. Build a strong foundation in cell biology and biochemistry early on, since later topics on genetics, ecology and physiology all draw on these core concepts.