Free Inorganic Ions OCR A Level Biology revision notes – covering specification point 2.1.2(p).
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Inorganic Ions
Inorganic ions are essential to the maintenance of physical structures and physiological mechanisms in organisms. A lack of an inorganic ion can result in deficiency symptoms or diseases.
Positive ions are called cations, and negative ions are called anions.
The table below lists the common cations:
| Name | Symbol |
|---|---|
| Calcium | Ca²⁺ |
| Sodium | Na⁺ |
| Potassium | K⁺ |
| Hydrogen | H⁺ |
| Ammonium | NH₄⁺ |
The table below lists the common anions:
| Name | Symbol |
|---|---|
| Nitrate | NO₃⁻ |
| Hydrogencarbonate | HCO₃⁻ |
| Chloride | Cl⁻ |
| Phosphate | PO₄³⁻ |
| Hydroxide | OH⁻ |
These inorganic ions will appear throughout the biological processes studied throughout the AS and A level course. You are expected to recognise and recall their symbols.