Mass Transport - Haemoglobin

Question 1

What does the quaternary structure of a haemoglobin molecule involve?

Answer 1

• All four polypeptides are associated with a haem group which contains a Fe2+ ion.
• Each Fe2+ ions can combine with an O2 molecule.
• Allows four O2 molecules to be transported in a single molecule of haemoglobin.

Question 2

Where does the loading of Oxygen occur?

Answer 2

Lungs

Question 3

Where does the unloading of oxygen occur?

Answer 3

Tissues

Question 4

What does it mean if a molecule of Haemoglobin has a high affinity for Oxygen?

Answer 4

• Associates with oxygen more easily

- Disassociates with oxygen less easily

Question 5

What does it mean if a molecule of Haemoglobin has a low affinity for Oxygen?

Answer 5

• Associates with oxygen less easily

- Disassociates with oxygen more easily

Question 6

What is the role of haemoglobin?

Answer 6

• To readily associate oxygen at the surface where gas exchange takes place
• To readily dissociate from oxygen at tissues

Question 7

What is the effect of CO2 on Haemoglobin?

Answer 7

• Changes shape so that it binds more loosely to O2

- Allows O2 to be released

Question 8

Where is O2 concentration high?

Answer 8

Gas Exchange Surfaces

Question 9

Where is O2 concentration low?

Answer 9

Respiring Tissues

Question 10

Why do different haemoglobins have different affinities for oxygen?

Answer 10

• Adapted for a specific species

- Different amino acid sequences

Question 11

What does the oxygen dissociation curve show?

Answer 11

The relationship between oxygen partial pressures