Water, ATP and inorganic ions

Why is water a polar molecule ?

O is more electronegative than H so attracts the shared pair of electrons in the covalent bond stronger forms a dipole (delta negative and delta positive)

State 4 biologically important properties of water

Metabolite/ solvent for chemical reactions

High specific heat capacity

High latent heat of vaporisation

Cohesion between molecules

Why is water significant to living organisms

Solvent for polar molecules during metabolic reactions

Enable organisms to avoid fluctuations in core body temperature

Cohesion- tension of water molecules in the transpiration stream

What are inorganic ions and where are they found?

Ions that don’t contain carbon atoms

Found in cytoplasm and extracellular fluid

Can be in higher/ lower concentrations to establish electrochemical gradients

Explain the role of hydrogen ions in the body.

High concentration of H ions - low (acidic) pH

H ions interact with the H bonds and ionic bonds in tertiary structure of proteins causing them to denature

Explain the role of iron ions in the body

Iron (2+) bonds to porphyrin ring to form haem group in haemoglobin

Haem group has a binding site to transport 1 molecule of oxygen around body in bloodstream

4 haem groups per haemoglobin molecule

Explain the role of sodium ions in the body

Involved in co-transport for the absorption of glucose and amino acids in the lumen of the gut

Involved in propagation of action potential in neurons

Explain the role of phosphate ions in the body

Component of:

DNA

ATP

NADP

CAMP