Haemoglobin

Question 1

What is the structure of haemoglobin?

Answer 1

2 alpha chains
2 beta chains
prosthetic group: haem - Fe2+

Question 2

What is the partial pressure of a gas?

Answer 2

pressure of a particular gas which contributes to the total pressure of gas mixture

Question 3

What is the relationship between pO2 and stauration of haemoglobin?

Answer 3

start: slow increase in saturation -> hard for first O2 to bind
rapid increase in saturation as easier for subsequent O2 to bind (cooperative binding)
slows down towards 100% as less likely O2 collide with unoccupied haem group

Question 4

What happens to haemoglobin when 1 O2 binds?

Answer 4

conformational change
haemgroups become more exposed

Question 5

Why doesn’t haemoglobin unload oxygen before reaching respiring tissue?

Answer 5

pO2 is not low in arteries due to thick wall

Question 6

What is the bohr effect?

Answer 6

fall in pH reduces the affinity of haemoglobin for oxygen causing increased unloading of O2 from haemoglobin

Question 7

Why does the bohr effect happen?

Answer 7

increased CO2 causes formation of carbonic acid which lowers pH

Question 8

Why is the bohr effect advantageous to metabolically active tissue?

Answer 8

rate of respiration increases and pCO2 increases causing rapid unloading
therefore plenty oxygen for aerobic respiration (less lactic acid produced)