Haemoglobin Flashcards
(11 cards)
The role of haemoglobin
An important part of the circulatory system
Found in red blood cells
Haemoglobin features
A large protein with a quaternary structure made of four polypeptide chains
Each chain has a haem group which contains an iron ion
Each molecule of human haemoglobin can carry four oxygen molecules
What is oxyhemoglobin
Where oxygen joins haemoglobin
It’s a reversible reaction
Loading definition
Unloading definition
Loading - when oxygen joins haemoglobin
Unloading - when oxygen leaves oxyhaemoglobin
What is affinity for oxygen
The tendency a molecule has to bind with oxygen
What affects partial pressure of oxygen
The affinity for oxygen
The greater the concentration of dissolved oxygen in cells the higher the partial pressure
So as partial pressure increases haemoglobin affinity for oxygen increases as:
- oxygen loads onto the haemoglobin to form oxyhemoglobin where there’s a higher partial pressure
- oxyhemoglobin unloads it’s oxygen where there’s a lower partial pressure
What does it means if there is a high affinity for oxygen
There is a high percentage of saturation of oxygen
What is the Bohr effect
An effect by which an increase of carbon dioxide in the blood results in a reduction of haemoglobins affinity for oxygen
When does the dissociation curve move right
When cells respire they produce carbon dioxide which raises the partial pressure
This increases the rate of oxygen unloading so it shifts right
What different types of haemoglobin depend on
Low oxygen environments
High activity levels
Size
