Water as a transport medium

• Water molecules are polar due to a separation of charge due to electrons being more attracted to the oxygen atom

  
• What is a dipole?

  a molecule which has a separation of charge due to difference in electro negativity. This results in a slightly positive and slightly negative region
• Why does water’s dipole nature make it good at transporting substances?

  They make good solvents by surrounding charged particles (form attractions between the charged ends of the water and the polar molecules)
• how does waters high specific heat capacity allow animals to maintain a constant internal body temperature?
• why are water molecules highly cohesive?

  Hydrogen bonding.
• what does it mean that water is highly cohesive?

  water molecules are bonded by strong hydrogen bonds, meaning that they are attached to each other and therefore flow in a stream
• how does water’s low viscosity allow it to be a good solvent?

  water molecules can slide over one another easily, allowing water to flow
• What is water adhesion?

  The tendency of water molecules to be attracted to and adhere to other substances due to the polarity of the molecule
• How do cohesion and adhesion make water a good transport medium?

  Adhesion allows water molecules to stick to the walls of blood vessels, combined with cohesion, water molecules are pulled upwards in a constant stream against gravity
• how does water’s high specific heat capacity relate to it’s ability as a good transport medium?

  water can absorb a lot of energy before undergoing a change in temperature. This allows stable internal temperatures to be maintained, this is crucial for the functioning of enzymes in metabolic reactions
• How does water stabilize the internal temperature of organisms?

  It resists rapid change in temperature due to high specific heat capacity, this results in the properties of the transport medium remain constant to continue efficient flow
• How does surface tension benefit aquatic organisms?

  The cohesive forces of water due to hydrogen bonds act as a surface for insects to use as a habitat on the surface of the water. this occurs due to there being no water molecules above the water at the surface for the molecules to bond with, leaving an inwards force where the water molecules at the surface are pulled closer together
• Explain why water is a good solvent?

  water is a dipolar molecule with a slightly positive and slightly negative region

  this means that it surrounds charged particles allowing them to dissolve

  and forms hydrogen bonds with them