Inorganic Ions- MARCROnutrients
These are needed in SMALL amounts! E.g.:
MAGNESIUM: in chlorophyll in leaves!
IRON: in haemoglobin in blood!
PHOPHATE: in plasma membrane, nucleic acids, ATP
CALCIUM: in bones and teeth
is essential as a medium for metabolic reactions.
It is a constituent of cells;
key elements are found in aqueous solution;
it provides a habitat for aquatic organisms.