Hydrogen ions lower pH of solutions, impacting enzyme and haemoglobin function; used in chemiosmosis (OP in Photosynthesis)
Iron ions are a component of haemoglobin allowing oxygen to be transported around the body
Sodium ions co-transport with glucose in the ileum cells, they are also used to create an actionpotential in synpases, they are also used in reducing waterpotential in Nephrons
Phosphate ions are components of DNA and ATP, and are involved in energy transfer