1: BIOLOGICAL MOLECULES - INORGANIC IONS

Question 1

What is an ion?

Answer 1

an atom/a molecule that has an electric charge due to gaining/losing electrons

Question 2

What is a cation?

Answer 2

an ion with a +ve charge

Question 3

What is an anion?

Answer 3

an ion with a -ve charge

Question 4

What is an inorganic ion?

Answer 4

an ion that doesn’t contain carbon

Question 5

Where are inorganic ions found?

Answer 5

in solution:
- cytoplasm of cells
- tissue/interstitial fluid
- blood
- lymph
- kidney filtrate

Question 6

What are some examples of inorganic ions?

Answer 6

• Fe^2+ (iron) ions
• H^+ (hydrogen) ions
• Na^+ (sodium) ions
• PO4^3- (phosphate) ions

Question 7

What is the role of Fe^2+ (iron) ions?

Answer 7

• haemoglobin is a large protein that carries O2 around the body in red blood cells
• haemoglobin is made up of 4 different polypeptide chains with an Fe^2+ ion in the centre
• its the Fe^2+ ion that binds to the O2 to form oxyhemoglobin
• when Fe^2+ ions bind to O2 they temporarily become Fe^3+ ions until O2 is released

Question 8

What is the role of H^+ (hydrogen) ions?

Answer 8

• pH is calculated based on the conc. of H^+ ions
• the more H^+ ions present, the lower the pH
• enzyme controlled reactions are all affected by pH

Question 9

How do you calculate pH?

Answer 9

pH = -log10 x no. of H^+ ions

Question 10

What is the role of Na^+ (sodium) ions?

Answer 10

glucose/amino acid molecules can be transported into a cell alongside Na^+ ions (co-transport)

Question 11

What is the role of PO4^3- (phosphate) ions?

Answer 11

• form phosphate groups
• DNA, RNA and ATP all contain phosphate groups
• in ATP bonds between phosphate groups store energy
• phosphate groups in DNA and RNA allow nucleotides to join together to form polynucleotide chains