Biology Notes: Water and its properties: Surface tension

Property: High surface tension and cohesion (adhesion and cohesion)

• Cohesion is the force whereby individual molecules stick together.
• Adhesion is the force whereby water molecules stick to other surfaces.

Biological role

• Cohesion helps water to move as an unbroken column in the xylem tubes in plants.
• Adhesion helps the water to stick to the inside of the vascular bundle.
• High surface tension resulting from high cohesion forces enable small organisms such as insects to skate the surface of the water.

Property: Water as a reagent

• Water is biologically significant as an essential metabolite, that is, it participates in the chemical reactions of metabolism.
• For example water is used as a source of hydrogen in photosynthesis and in hydrolysis reactions, condensation and respiration.

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