transport of carbon dioxide

Question 1

what effect does carbon dioxide have on the psoition of the oxygen dissociation curve

Answer 1

causes the curve to move to the right has carbon dioxide has a higher affinity for haemoglobin, therefore has partial pressure of CO2 increase Hb has a lower affinity for oxygen so oxygen dissociates, even at higher partial pressures

Question 2

what is the Bohr effect

Answer 2

the shift in the graphs position to the right accounting for the unloading of oxygen from oxyhaemoglobin in respiring tissues where the partial pressure of Carbon dioxide is higher causing a lower affinity for oxygen as it is released into respiring tissue

Question 3

How is carbon dioxide transported

Answer 3

1) in solution in the plasma (5%)
2) As a hydrogen carbonate ion (85%)
3) bound to a haemoglobin as carbamino-haemoglobin (10%)

Question 4

outline the reaction in the cell with carbon dioxide

Answer 4

1) CO2 diffuses in the blood and diffuses into the red blood cell
2) CO2 reacts with the water of the cell, catalysed by carbonic anhydrase, forming carbonic acid
3) carbonic acid dissociates into a hydrogen ion and a bicarbonate ion
4) bicarbonate ions diffuse out the red blood cells into the plasma
5) Bicarbonates have a negative charge so to balance out the outflow of negative ions chloride ions diffuse into the RBC via the chloride shift
6) H+ ions cause oxyhaemoglobin to dissociate oxygen.
7) H+ ions combine with Hb to make haemoglobinic acid
8) oxygen diffuses out of RBC into tissues

Question 5

define the chloride shift

Answer 5

the movement of chloride ions into the red blood cell to maintain electrochemical neutrality as it balances out the negative charge due to the loss of bicarbonate ions into the blood plasma

Question 6

how does the PH of the red blood cell not fall during the transport of carbon dioxide

Answer 6

the combining of H+ ions with haemoglobin making haemoglobininic acid removes hydrogen ions out the blood cell so PH of blood doesn’t fall

Question 7

explain what happens when more CO2 is produced in muscles

Answer 7

• more CO2 produces more H+
• H+ combines with haemoglobin causing the dissociation of oxygen
• oxygen is dissociated into respiring cells
• the harder the muscle is working the more co2 is produced so the more oxygen is dissociated in that area ( high partial pressures of CO2 and low partial pressures of oxygen )