1.3.2 Explain the importance of water as a solvent in transport, including its dipole nature.

A polar molecule is one that has a slight negative side and a slight positive side.

for a molecule to be polar it has to be dipole; that is, its charge is separated around the molecule into a more negative area and a more positive area. 

this is the case with water molecules - H₂O : oxygen has 8 protons (whereas hydrogen has only one); so the attractive force from oxygen’s nucleus is stronger than that of hydrogens’; so the shared electrons are pulled closer to the oxygen side of the bond; so oxygen gains a slight negative charge (this is the negative area) and hydrogen gains a slight positive charge (this is the positive area). 

this also makes water a solvent: being a charged/polar/dipole molecule allows it to attract and dissociate (dissolve) other polar particles (solutes) such as proteins, ions (e.g. Na⁺Cl^-) and glucose

this is why water is the transport medium in tissue fluid, blood and lymph: it can dissolve and transport many substances.