ZIMSEC O Level Biology Notes:Properties and Biological significance of water

Property: Transport medium

  • Water is a neutral liquid medium because it has a pH of 7.

Biological role of this property

  • Water’s solvent properties also mean that it acts as a transport medium in the blood transporting cells, lymphatic and excretory system, the alimentary canal and in the xylem and phloem.

Property: High heat capacity

  • Water has a high heat capacity of 4 200 J.
  • This means that a large increase in heat energy results in a relatively small rise in temperature.
  • This is because much of the energy is used in breaking the hydrogen bonds which restrict the mobility of the molecules.
  • Therefore temperature changes of water are minimized as a result of its high heat capacity.

Biological role

  • It makes it easier to achieve a stable body temperature.

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