bohr effect/shift (ocr)

adamscott

i really dont understand the bohr effect. could someone try and explain it for me please? :confused:

Reply 1

fakeplastictree

Ok i'll do my best...

At the lungs/gaseous exchange surfaces there is a high partial pressure of oxygen, and a low partial pressure of CO2. As a result of the low partial pressure of carbon dioxide, haemoglobin has a high affinity for 02 and readily associates at these gas exchange surfaces. THE DISSOCIATION CURVE IS SHIFTED TO THE LEFT.

At the respiring tissues, there is a high partial pressure of CO2 (respiration product etc) and a low partial pressure of O2. As a result haemoglobin's affinity for oxygen is reduced, meaning oxygen readily disscoiates from Hb at the respiring tissues. THE DISSOCIATION CURVE IS SHIFTED TO THE RIGHT

So basically the Bohr effect is a result of Hb changing affinity for O2 under different concentrations of carbon dixoide. This is mainly a result of the acid nature of carbon dioxide, and the way in which it forms hydrogen and hydrogen carbonate ions - therefore haemoglobonic acid (causes to oxygen to dissociate in acidic conditions).

Hope that helps!

Reply 2

Iscariot

Wikipedia rampage!

http://en.wikipedia.org/wiki/Bohr_shift

Reply 3

Excalibur

Bohr effect - the way the dissociation curve shifts to the right at low oxygen concentrations (high CO2 concentrations), so that Hb has a reduced affinity for O2 and unloads O2 where oxygen is most needed.

Carbon dioxide in the blood reacts with water to produce carbonic acid (H2CO3), which dissociates into HCO3- (hydrogencarbonate) ions and H+ ions. The Hb reacts with the H+ ions to form haemoglobinic acid and in doing so unloads the oxygen it was carrying. The oxygen diffuses out of the Hb and into the blood.

Reply 4

Wangers

^ Impressive. OP - Note that an increase in P[CO2] means that more oxyheamoglobin disociates in that particular enviroment. Hence muscles etc are supplied with oxygen, when otherwise heamoglobins affinity for O2 would be too high.

OP - check if you understand

Consider a diver, he takes several deep in and out brethes before diving with a N2/O2 tank, he faints soon after - explain how this could have happened. - Not strictly on Q....