Transport of oxygen Flashcards
What is haemoglobin?
A globular prosthetic quaternary protein with 4 subunits 2 alpha and 2 beta subunits called haem groups with Fe2+.
What is the function of the iron ions in the haemoglobin?
It binds to the oxygen
Where is the haemoglobin found/?
In red blood cells
How does the Hb bind to the oxygen?
It has a high affinity for the oxygen
How is oxygen transported throughout the body?
In the haemoglobin in the red blood cells.
How many oxygen molecules bind to each haem group?
1
How is the oxygen released into the respiring cells?
It dissociates from the Hb and diffuses into the cells
How is the concentration of oxygen measured?
The relative pressure that it contributes to a mixture of gases, which is the partial pressure of oxygen.
What shape does a % saturation against partial pressure of oxygen make?
An S-shape curve
What happens to Hb and oxygen at low partial pressures?
The first oxygen molecule is reluctant to bind to the first haem group, because the first haem group is hard to reach because it is in the middle of the haem group, so there is a low saturation of haemoglobin at a low partial pressure of oxygen
What happens to Hb and oxygen at medium partial pressures?
Because the first oxygen that was bound to the Haem group changed the haemoglobin’s shape, the need to oxygen molecules can more easily bind to 2 haem groups. This is where the rate of % saturation increases
What is conformational change?
The change in the haem group from the 1st oxygen molecule being added to make the next 2 easier
What happens to Hb and oxygen at high partial pressures?
The oxygen find it difficult to bind to the haem group because the haemoglobin’s shape changed again.
What is fetal haemoglobin?
This is the blood found in a feutus
What is the difference between adult and fetal haemoglobin?
Fetal Hb has a higher affinity for oxygen than adult Hb
Why is there a difference between the adult and fetal haemoglobin?
It needs to be able to get the adult Hb to dissociate with their oxygen so that they can associate with it. It is because The fetal Hb needs to ab able to associate with oxygen in an environment where the oxygen partial pressure is low enough to get it to dissociate from the adult HB.
What happens in the placenta?
The oxygen partial pressure is low so the fetal Hb will absorb oxygen from the surrounding fluid, reducing the partial pressure further. This makes the adult Hb dissociate it oxygen in the placenta. decreasing the partial pressure of the placenta so it releases more oxygen.
What direction is the fetal Hb curve compared to the adult Hb curve?
The fetal Hb curve is on the left of the adult Hb curve
