Topic 1---B: More biological molecules- 5. Inorganic ions

Question 1

What are ions?

Answer 1

An ion is an atom or group of atoms that has an electric charge

Question 2

What is an ion with a positive charge called?

Answer 2

Cation

Question 3

What is an ion with a negative charge called?

Answer 3

Anion

Question 4

What is an inorganic ion?

Answer 4

It’s an ion which doesn’t contain carbon

Question 5

Hydrogen ions

Answer 5

• pH is calculated based on the concentration of hydrogen ions
• The more hydrogen ions present the lower the pH (more acidic environment)

Question 6

Sodium ions

Answer 6

• Glucose and amino acids need a bit of help crossing cell membranes
• A molecule of glucose or an amino acid can be transported into a cell across the cell-surface membrane alongside sodium ions.

Question 7

Iron ions in haemoglobin

Answer 7

• Haemoglobin is made up of 4 different polypeptide chains each with an iron ion in the centre.
• It’s the iron ion that actually binds to the oxygen in haemoglobin

Question 8

Phosphate ions

Answer 8

• When a phosphate ion is attatched to another molecule it’s known as a phosphate group.
• It’s the bonds between phosphate groups that store energy in ATP
• The phosphate groups in DNA, RNA allow nucleotides to join up to form polynucleotides.