3.1.7 Water

Question 1

Why is water a polar molecule?

Answer 1

Oxygen is more electronegative than hydrogen, so attracts the electron density in the covalent bond more strongly.
So oxygen has a partial negative charge and hydrogen has a partial positive charge.

Question 2

State 4 biologically important properties of water.

Answer 2

• Metabolite/solvent for chemical reactions in the body.
• High specific heat capacity
• High latent heat of vaporisation
• Cohesion between molecules.

Question 3

Explain why water is significant to living organisms.

Answer 3

• Solvent for polar molecules during metabolic reactions
• Enables organisms to avoid fluctuations in core temperature
• Cohesion-tension of water molecules in transpiration stream