Structure Of Haemoglobin

Question 1

Describe the structure of haemoglobin.

Answer 1

1. Four polypeptide chains linked together.
   —> 2x alpha glucose & 2x beta glucose
2. Forms a quaternary structure.
3. Each is folded into a specific shape due to the presence of one haem group containing an iron ion (Fe2+)
   —> Each Fe2+ binds to one O2 molecule

Question 2

What is co-operative binding?

Answer 2

• Binding of the first O2 molecule to a haem group changes the quaternary structure.
• This uncover a haem group, thus making the binding of a second O2 molecule easier, and so on, to a maximum of 4 O2 molecules.