Gas exchange - haemoglobin & oxygen Flashcards
What is the primary function of haemoglobin?
Binding oxygen in our blood
What type of proteins are haemoglobins?
Globular proteins found in red blood cells
How many polypeptide subunits does each haemoglobin molecule consist of?
Four polypeptide subunits
What is located at the center of each haemoglobin subunit?
An iron-containing haem group
How many oxygen molecules can each haemoglobin molecule transport?
Four oxygen molecules
What is the term for the pressure exerted by a single gas in a mixture?
Partial pressure
What is the symbol for partial pressure?
p
What is denoted as pO2?
The partial pressure of oxygen
What phenomenon describes the change in haemoglobin’s shape after the first oxygen molecule binds?
Cooperative binding
What does the affinity of haemoglobin for oxygen describe?
The ease with which haemoglobin binds and dissociates with oxygen
Where is the affinity of haemoglobin for oxygen high?
In areas of high partial pressures of oxygen, such as the alveoli of the lungs
Where is the affinity of haemoglobin for oxygen low?
In areas of low partial pressures of oxygen, such as respiring muscle cells
What is the significance of foetal haemoglobin having a higher affinity for oxygen than adult haemoglobin?
It allows a foetus to obtain oxygen from its mother’s blood at the placenta
What is the oxygen dissociation curve?
A graph representing the percentage saturation of haemoglobin at different partial pressures of oxygen
How does the oxygen dissociation curve for foetal haemoglobin compare to that of adult haemoglobin?
It shifts to the left, indicating higher percentage saturation at any given partial pressure
What happens to foetal haemoglobin after birth?
It is gradually replaced by adult haemoglobin
What are proteins like haemoglobin that can exist in multiple conformations called?
Allosteric proteins
What is the effect of carbon dioxide on haemoglobin?
It acts as an allosteric inhibitor, lowering the affinity for oxygen
How does carbon dioxide affect foetal haemoglobin compared to adult haemoglobin?
It has less of an allosteric effect on foetal haemoglobin
Fill in the blank: The ability of haemoglobin to change shape once oxygen binds is due to _______.
Cooperative binding
