3.1.2i) The role of haemoglobin in transporting oxygen and carbon dioxide

Question 1

Erythrocytes specialised features

Answer 1

Biconcave shape
Large SA - increasing SA available for diffusion of gases
Small size - to pass through narrow capillaries
Continuously made in the red bone marrow in adults
When mature erythrocytes enter the circulation they have lost their nuclei - maximises the amount of so they only last for about 120 days in the bloodstream

Question 2

Haemoglobin

Answer 2

A very large globular conjugated protein
4 peptide chains with an iron containing haem prosthetic group
300 million haemoglobin molecules in each red blood cell & each haemoglobin molecules in each red blood cell & each haemoglobin molecule can bind to 4 oxygen molecules

Question 3

Oxyhaemoglobin

Answer 3

Oxygen binding loosely to the haemoglobin
reversible reaction
Hb + 4O₂ ⇌ Hb(O₂)4