Cambridge (CIE) AS Your notes
Biology
Water
Contents
The Role of Water in Living Organisms
Water & the Hydrogen Bond
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, The Role of Water in Living Organisms
Your notes
Water Molecules: In Living Organisms
Water has many essential roles in living organisms due to its properties:
The polarity of water molecules
The presence and number of hydrogen bonds between water molecules
Solvent
As water is a polar molecule many ionic compounds (e.g. sodium chloride) and
covalently bonded polar substances (e.g. glucose) will dissolve in it
This allows chemical reactions to occur within cells (as the dissolved solutes are
more chemically reactive when they are free to move about)
Metabolites can be transported efficiently (except non-polar molecules which are
hydrophobic)
Polarity of Water Diagram
Due to its polarity water is considered a universal solvent
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Biology
Water
Contents
The Role of Water in Living Organisms
Water & the Hydrogen Bond
© 2025 Save My Exams, Ltd. Get more and ace your exams at savemyexams.com 1
, The Role of Water in Living Organisms
Your notes
Water Molecules: In Living Organisms
Water has many essential roles in living organisms due to its properties:
The polarity of water molecules
The presence and number of hydrogen bonds between water molecules
Solvent
As water is a polar molecule many ionic compounds (e.g. sodium chloride) and
covalently bonded polar substances (e.g. glucose) will dissolve in it
This allows chemical reactions to occur within cells (as the dissolved solutes are
more chemically reactive when they are free to move about)
Metabolites can be transported efficiently (except non-polar molecules which are
hydrophobic)
Polarity of Water Diagram
Due to its polarity water is considered a universal solvent
© 2025 Save My Exams, Ltd. Get more and ace your exams at savemyexams.com 2
