The Bohr Shift

Question 1

Bohr effect, or Bohr shift
is

Answer 1

Changes in the oxygen dissociation curve as a result of carbon dioxide levels

Question 2

When the partial pressure of carbon dioxide in the blood is high, haemoglobin’s affinity for oxygen is

Answer 2

reduced

Question 3

When the partial pressure of carbon dioxide in the blood is high, haemoglobin’s affinity for oxygen is reduced

This is the case in respiring tissues, where cells are producing carbon dioxide as a waste product of respiration

This occurs because CO2 lowers

Answer 3

the pH of the blood

Question 4

Why does carbon dioxide reduce the ph of blood

Answer 4

CO2 combines with water to form carbonic acid

Carbonic acid dissociates into hydrogen carbonate ions and hydrogen ions

Hydrogen ions bind to haemoglobon, causing the release of oxygen

Question 5

CO2 combines with water to form carbonic acid

Carbonic acid dissociates into hydrogen carbonate ions and hydrogen ions

Hydrogen ions bind to haemoglobon, causing the release of oxygen

is helpful as

Answer 5

This is a helpful change because it means that haemoglobin gives up its oxygen more readily in the respiring tissues where it is needed

Question 6

On a graph showing the dissociation curve, the curve shifts to the right when CO2 levels increase
This means that

Answer 6

at any given partial pressure of oxygen, the percentage saturation of haemoglobin is lower at higher levels of CO2