Biological Molecules: Inorganic Ions

Question 1

What are inorganic ions?

Answer 1

• An ion is an atom (or group of atoms) that has an electric charge
• Inorganic ions are ions without carbon

Question 2

Where are inorganic ions found?

Answer 2

• Found in solution in the cytoplasm and body fluids of organisms
• Some found in low or high concentrations

Question 3

Role of Hydrogen Ions

Answer 3

• H+ ions affect pH
• pH is a measure of the concentration of H+ ions
• H+ ions interact with H-bonds & ionic bonds in tertiary structure of proteins, which can cause them to denature

Question 4

Role of Iron Ions

Answer 4

• Iron ions are a component of haemoglobin
• Haemoglobin is a large protein that carries oxygen around the body, in red blood cells
• Haemoglobin is made of four different polypeptide chains, each with an iron ion (Fe2+) in the centre
• Fe2+ bind to the oxygen and temporarily become Fe3+ until oxygen is released

Question 5

Role of Sodium Ions

Answer 5

• Involved in co-transport for absorption of glucose & amino acids in lumen of gut

Question 6

Role of Phosphate Ions

Answer 6

• When a phosphate ion (PO4^3-) is attached to another molecule, it’s known as a phosphate group
• Phosphate groups are a component of DNA, ATP and RNA
• ATP - The bonds between phosphate groups store energy in ATP
• DNA & RNA - the phosphate groups allow nucleotides to join up to form polynucleotides