3.3.4 Mass transport Flashcards
What is haemoglobin?
Haemoglobin is a water-soluble globular protein consisting of two beta polypeptide chains and two alpha helices, each forming a complex with a haem group.
How many oxygen molecules can each haemoglobin molecule carry?
Each haemoglobin molecule can carry four oxygen molecules.
How does the partial pressure of oxygen affect haemoglobin’s affinity for oxygen?
As the partial pressure of oxygen increases, haemoglobin’s affinity for oxygen increases, leading to tighter binding of oxygen.
What happens to haemoglobin’s affinity for oxygen during respiration?
During respiration, the partial pressure of oxygen decreases, reducing haemoglobin’s affinity for oxygen and causing oxygen to be released in respiring tissues.
What is an oxygen dissociation curve?
An oxygen dissociation curve illustrates the change in haemoglobin saturation as the partial pressure of oxygen changes, showing how haemoglobin’s affinity for oxygen varies with oxygen concentration.
What is positive cooperativity in the context of haemoglobin binding?
Positive cooperativity refers to the phenomenon where the binding of the first oxygen molecule to haemoglobin increases its affinity for subsequent oxygen molecules, making it easier for additional oxygen molecules to bind.
How does fetal haemoglobin differ from adult haemoglobin in terms of oxygen affinity?
Fetal haemoglobin has a higher affinity for oxygen compared to adult haemoglobin, allowing it to absorb oxygen more effectively at the lower partial pressures found in the placenta.
What is the Bohr effect?
The Bohr effect is the decrease in haemoglobin’s affinity for oxygen in the presence of carbon dioxide, which causes oxygen to be released. This happens because carbon dioxide creates slightly acidic conditions that change the shape of the haemoglobin protein.
