The respiratory process involves hemoglobin (Hgb), an iron-containing compound found in red blood cells. In the process, carbon dioxide diffuses from tissue cells as molecular CO₂, while O₂ simultaneously enters the tissue cells. A significant fraction of the CO₂ leaving the tissue cells enters red blood cells and reacts with hemoglobin; the CO₂ that does not enter the red blood cells (1 in the figure below) remains dissolved in the blood and is transported to the lungs. Some of the CO₂ entering the red blood cells reacts with hemoglobin to form a compound (Hgb⋅CO₂; 2 in the figure). When the red blood cells reach the lungs, the Hgb⋅CO₂ dissociates, releasing free CO₂. Meanwhile, the CO₂ that enters the red blood cells but does not react with hemoglobin combines with water to form carbonic acid, H₂CO₃, which then dissociates into hydrogen ions and bicarbonate ions (3 in the figure). The bicarbonate ions diffuse out of the cells (4 in the figure), and the ions are transported to the lungs via the bloodstream.

For adult humans, every deciliter of blood transports a total of 1.6 10^–4 mol of carbon dioxide in its various forms (dissolved CO₂, Hgb CO, and bicarbonate ions) from tissues to the lungs under normal, resting conditions. Of the total CO₂, 1.1 × 10^–4 mol are transported as bicarbonate ions. In a typical resting adult human, the heart pumps approximately 5 liters of blood per minute. You have been asked to determine how many moles of CO₂ are dissolved in blood and how many moles of Hgb CO₂ are transported to the lungs during an hour's worth of breathing.

(a) Draw and fully label a flowchart and do a degree-of-freedom analysis. Write the chemical reactions that occur, and generate, but do not solve, a set of independent equations relating the unknown variables on the flowchart.

(b) If you have enough information to obtain a unique numerical solution, do so. If you do not have enough information, identify a specific piece/pieces of information that (if known) would allow you to solve the problem, and show that you could solve the problem if that information were known.

Transcribed Image Text:

Blood Sto the lungs.. CO2 Red Blood Cell Dto the lungs. to the lungs...