Friday, July 13, 2012

STPM Biology - chapter 1: Reision essay question 28


28. Describe 4 properties which render water to be an important medium for life. [8]

Answer:

A)     # Solvent
-water is a polar/ dipolar/ charged molecules
-solubilize most of biological molecules/ medium for biological reaction/ ionic solids/ nutrient substances.
-due to the hydrogen bonding.

# High heat capacity/high latent heat of vaporization.
-good in maintaining against temperature fluctuation/ stabilize temperature.
-high boiling point.
-Vaporization leads to the cooling effect.

# High surface tension
-formation of plasma membrane/ micelle.
-cohesion and adhesion forces for movement of water up a capillary.

# maximum density of water at 4ºC/ ice float on water.
-water increases in volume and reduces in density as temperature drops
-this ensure aquatic organism to survive in freezing water/ ice is a insulator of heat.

# low viscosity
-acts as lubricant/ low resistant for movement.

Assignment submitted by L.E., Teh, E.L., Wong, Tan Findy 2011/2012 (IBM)







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