what is the difference between haemoglobin a and haemoglobin S

Question

anonymous · Answer

Well, hemoglobin A is a normal human hemoglobin. 
It does what it's supposed to: 
it helps our red blood cells carry oxygen. 

~~~~~~~~

On the other hand, 
hemoglobin S is an ABNORMAL hemoglobin. It's not normal. 
Hemoglobin S causes our red blood cells to sort of curl up into an S shape. 
And when this happens, the red blood cells have trouble carrying oxygen. 

We call this condition "sickle cell anemia." 

That's why it's called Hemoglobin S. 
S is for Sickle Cell.