Haemoglobin Mass transport in animals

Created by

Mahima Ali

Cards (30)

What is the structure Haemoglobin?
A globular protein consisitng of 4 polypeptide chains, alpha and beta chains
Each has a haem group, containing a Iron 2+ ion
It has 4 oxygen binding sites
what is the function of haemoglobin?
Haemoglobin is found in red blood cells (erythrocytes). Haemoglobin allows red blood cells to transport oxygen from the lungs to all other parts of the body.
What is affinity?
the strength of the attaction between two substances
When haemoglobin is bound to oxygen, it’s called…
Oxyheamoglobin
What structure does heamoglobin have?
Quaternary
How many oxygen molecules can one iron atom bind to?
1
When an oxygen molecule binds to an iron atom in haemoglobin, this causes changes to the quaternary
structure of the haemoglobin.
what is positive cooperativity?
When an oxygen molecule binds to an iron atom in haemoglobin, haemoglobin’s quaternary structure changes. This uncovers more of the other iron atoms, making it easier for another oxygen molecule to bind.
The process of oxygen binding to hemoglobin is known as oxygen
association
The process of oxygen unbinding from hemoglobin is known as oxygen
dissociation
Positive cooperativity enables oxygen to…
rapidly associate with haemoglobin and rapidly dissociate from haemoglobin
When the partial pressure of oxygen is high…
assocaiation takes place
Oxygen association occurs in the lungs because…
the partial pressure of oxygen is higher in the lungs than in the blood.
Oxygen dissociation occurs in respiring tissues because…
the partial pressure of oxygen is lower in the tissues than in the blood.
oxygen diffuses down its pressure gradient.
As the partial pressure of oxygen increases, the percentage saturation of haemoglobin with oxygen increases
In the dissocation curve, there is a steep change due to what?
Positive cooperitivity.
Suggest why the percentage saturation of haemoglobin with oxygen does not reach 100⁢% in the lungs
The probability of a collision between an unbound iron atom and an oxygen molecule is low.
Most iron atoms are already bound to oxygen molecules.
why the gradient of the curve changes at the point indicated below.
The increase in gradient is due to positive cooperativity. When an oxygen molecule binds to haemoglobin, it makes it easier for another oxygen molecule to bind. This causes the percentage saturation of haemoglobin with oxygen to increase rapidly.
Whats a factor that affects the dissocation curve?
Carbon dioxide
with low levels of carbon dioxide, where does the curve shift?
Left
with high levels of carbon dioxide, where does the curve shift?
Right
If the curve shifts to the left, what does that mean?
At low concentrations of carbon dioxide, oxygen associates more readily and dissociates less readily
When the oxyhaemoglobin curve moves to the left or right as a result of carbon dioxide concentration, scientists call this the…
Bohr effect
When CO2 increases, what is the pH of the blood?
More acidic
CO2 itself isnt acidic, so how does that make the blood acidic?
CO2 reacts with water in the blood, releasing H+ ions which are acidic
Acidity can also affect the...
shape of molecules
What occurs when theres low acidity within the quaternary structure?
easier dissocation
Define the Bohr effect.
The shifting of the oxyhaemoglobin dissociation curve left or right as a result of carbon dioxide concentration.
Explain how the Bohr effect allows the body to meet the increased demand for oxygen in muscle cells during exercise.
During exercise, respiring muscle cells release carbon dioxide. This reacts with water in the blood to form H+ ions, decreasing the pH of the blood near the tissues. The acidic conditions cause haemoglobin to change shape, allowing oxygen to dissociate more readily. Therefore, active cells are provided with more oxygen for aerobic respiration.
Hyperventilation occurs when a person breathes too quickly, and exhales more carbon dioxide than usual.Predict the effect of hyperventilation on the oxyhaemoglobin dissociation curve.
When too much carbon dioxide is exhaled, the blood becomes less acidic and the oxyhaemoglobin dissociation curve shifts to the left. This means that haemoglobin binds with oxygen more readily and releases oxygen less readily. Therefore, tissues receive less oxygen for respiration, which can lead to symptoms including dizziness and fainting.
When oxygen associates less readily with haemoglobin, and dissociates more readily, scientists say that this haemoglobin has a…
lower affinity for oxygen