1.6.4 Inorganic Ions

Key Inorganic Ions and Their Roles:

1. Hydrogen ions ($H⁺$):

• Function: Determine pH in biological systems, such as blood.
• Key fact: The higher the concentration of hydrogen ions, the lower the pH.
• This is important for maintaining enzyme activity and other cellular processes.

2. Iron ions ($Fe²⁺$):

• Function: Component of haemoglobin, the oxygen-carrying molecule in red blood cells.
• Key fact: Iron ions bind reversibly to oxygen, allowing haemoglobin to transport oxygen throughout the body.

3. Sodium ions ($Na⁺$):

• Function: Play a crucial role in the co-transport of glucose and amino acids across cell membranes.
• Key fact: Sodium ions are actively transported out of cells, creating a concentration gradient essential for nutrient absorption.

4. Phosphate ions ($PO₄³⁻$):

• Function: A structural component of DNA and RNA (in the sugar-phosphate backbone) and a key part of ATP, the molecule used for energy in cells.
• Key fact: Phosphate ions are also involved in phosphorylation reactions, making molecules more reactive.

Importance in Biological Systems:

• Inorganic ions are vital for:
  • Cellular processes such as respiration, photosynthesis, and active transport.
  • Structural roles (e.g., DNA structure and haemoglobin).
  • Regulating pH and ensuring enzyme activity occurs at an optimal rate.