transport of carbon dioxide

Question 1

what is the effect of increasing co2 concentration and when does this happen

Answer 1

-when the partial pressure of o2 in respiring tissues is lower than lungs
-oxyhaemoglobin begins to dissociate and release o2 to tissues
-hb is available to take up hydrogen ions forming acid
-where tissues are very active, more co2 released

Question 2

what is the bohr effect

Answer 2

-the effect of increasing conc of co2 on the haemoglobin

Question 3

what effect does increasing co2 have on the haemoglobin

Answer 3

-co2 enters RBC forming carbonic acid which dissociates to release H+ ions
-H+ ions affect ph of cytoplasm making it more acidic
-the change in pH affects tertiary structure of haemoglobin reducing the affinity for o2
-haemoglobin unable to hold as much o2 and is release from oxyhb to tissues
-where more co2 present, hb becomes less saturated with 02
-so more o2 released where more co2 produced in respiration

Question 4

how is co2 transported

Answer 4

-dissolving in plasma
-forming carbaminohaemoglobin
-forming hydrogen carbonate ions HCO3-

Question 5

what happens at higher rates of respiration

Answer 5

-more co2
-so more H+ ions
-so more acidic
-so more hb releases o2

Question 6

what is the first step of the carbon dioxide in an erythrocyte

Answer 6

-co2 passes into plasma and RBC by diffusion
-co2 combines with water in cytoplasm to form carbonic acid

Question 7

what enzyme catalyses the reaction between co2 and water

Answer 7

-carbonic anhydrase

Question 8

what is the second step of the carbon dioxide in an erythrocyte

Answer 8

-carbonic acid dissociates to give hydrogen ions and hydrogen carbonate ions

Question 9

what is the third step of the carbon dioxide in an erythrocyte (hydrogen carbonate ions)

Answer 9

-hydrogen carbonate ions pass out of RBC by diffusion and chloride ions move in
-maintains the charge inside of the RBC
-called chloride shift

Question 10

what is the third step of the carbon dioxide in an erythrocyte (H+ ions)

Answer 10

-haemoglobin acts as a buffer and accepts hydrogen ions
-forms haemoglobinic acid
-this changes the pH of the blood

Question 11

what happens to the o2 dissociation curve as a result of the bohr effect (the effect of increasing conc of co2 on the haemoglobin)

Answer 11

-it is shifted down to the right

Question 12

what does the haemoglobin act as

Answer 12

a buffer

Question 13

what is prevented by the removal of hydrogen ions out of the solution

Answer 13

-as it associates with haemoglobin to produce haemoglobinic acid, it oprevents the contents of the RBC from becoming very acidic