1.7 Water, 1.8 Inorganic Ions

Why is water a polar molecule?

Water is polar because

● oxygen is more electronegative than hydrogen

● attracting electron density more strongly

●creating a slight negative charge δ- on oxygen and a slight positive charge δ+ on hydrogen.

What are 4 biologically important properties of water?

Water is a

● metabolite/solvent for chemical reactions in body

● has a high specific heat capacity

● a high latent heat of vaporization

● exhibits cohesion between molecules.

Why is water significant to living organisms?

Water acts as

● a solvent for polar molecules during metabolic reactions

● helps maintain core temperature

● facilitates cohesion-tension in the transpiration stream.

Describe water as a metabolite

● condensation reaction (removal of a water molecule to form a bond)

● hydrolysis reaction (water is added to break a chemical bond)

describe water as a solvent.

● Water is polar - many ions will dissolve

● allowing for chemical reactions to occur in cells

● transport of metabolites

Describe water 's high specific heat capacity

● many H bonds in water

● alot of energy to break bonds

● temperature of water is stable

● stable habitats, temperature regulation in an organism

Describe water's latent heat of vaporisation.

● large amount of energy required to change its state

● cooling effect for organisms

● little water evaporating loses great amount of heat

What are inorganic ions and where are they found in the body?

Inorganic ions are

● ions that do not contain carbon atoms

● are found in the cytoplasm and extracellular fluid

● often in varying concentrations.

What is the role of hydrogen ions in the body?

● High concentrations of H+ ions lead to low (acidic) pH

● H+ ions interact with hydrogen bonds and ionic bonds in tertiary structure proteins, causing denaturation.

What is the role of iron ions in the body?

● Iron ions (Fe2+) bond to the porphyrin ring to form the haem group in haemoglobin,

●Haem group has binding site to transport 1

molecule of O2 around body in bloodstream.

●4 haem groups per haemoglobin molecule.

What is the role of sodium ions in the body?

● Sodium ions are involved in co-transport for glucose and amino acids absorption in the gut

● involved in the propagation of action potentials in neurons.

What is the role of phosphate ions in the body?

Phosphate ions are components of

●DNA

●ATP

●NADP

●cAMP.