Possible Essay Qs

Question 1

GAS TRANSPORT STEP 1

Answer 1

CO2 diffuses out of the cells into systemic capillaries

Question 2

GAS TRANSPORT STEP 2

Answer 2

Only 7% of CO2 remains dissolved in plasma

Question 3

GAS TRANSPORT STEP 3

Answer 3

Nearly a fourth of CO2 enters RBCs and binds to hemoglobin, forming carbaminohemoglobin

Question 4

GAS TRANSPORT STEP 4

What enzyme catalyzes this reaction

Answer 4

70% of CO2 load enters RBCs and is first converted to carbonic acid, then dissociates into bicarbonate and H+. Hemoglobin buffers H+

Carbonic anhydrase

Question 5

GAS TRANSPORT STEP 5

Answer 5

Bicarbonate enters the plasma in exchange for CL- (chloride shift)

Question 6

GAS TRANSPORT STEP 6

Answer 6

At the lungs, dissolved CO2 diffuses out of the plasma and enters alveoli

Question 7

GAS TRANSPORT STEP 7

Answer 7

Law of mass action causes CO2 to unbind from hemoglobin and diffuses out of the RBC and then out of the plasma into the alveoli

Question 8

GAS TRANSPORT STEP 8

Answer 8

Carbonic acid reaction reverses, pulling HCO3- back into the RBC and converting it back to CO2. The CO2 diffuses out of the RBC and then out of the plasma and into the aleveoli