1. What causes O2 to move from the alveoli into the pulmonary capillaries?

2. What attributes of the respiratory membrane contribute to the efficiency of gas transport across the membrane?

3. In what form or how is most O₂ transported in the blood? What about CO₂?

4. The graph below shows O₂-dissociation curves for hemoglobin at two different pH values.

 

a. On average, how many molecules of O₂ are attached to hemoglobin at pH 7.4 at 40 mm Hg pO₂? What about at 25 mm Hg pO₂?

b. How does the shift to the right from pH 7.4 to pH 7.2 alter O₂ affinity of the hemoglobin?

c. How is this altered affinity important to organisms?

d. What would cause a pH difference between resting and active muscle?

 

5. Llamas live at high altitudes where atmospheric pO₂ is approximately 85 mmHg compared to 160 mm Hg at sea level. The hemoglobin molecule of these animals is somewhat different from human hemoglobin; it is able to pick up O₂ at lower pO₂. How would the O₂-hemoglobin dissociation curve for llama hemoglobin compare to the O₂-dissociation curve for human hemoglobin?