The following table shows the partial pressure of oxygen and carbon dioxide in four places in human body. Use the information given in the tables to describe the process of exchange between alveolar air and deoxygenated blood.

It is given that the partial pressure of oxygen (PO 2 ) in the alveoli is 13.9 while the same in the deoxygenated blood inside the blood capillaries is 5.3. The exchange of gases across the respiratory surfaces takes place by diffusion. The gases always diffuse from a region of high partial pressure to the region of low partial pressure. Thus, the oxygen will diffuse from the alveoli into the lung capillaries. Similarly, the partial pressure of carbon dioxide (PCO 2 ) in the alveolar air is 6 while in the lung capillaries is 5.3. Thus, the Co 2 will diffuse from deoxygenated blood of capillaries to the lung alveoli.

The following table shows the partial pressure of oxygen and carbon dioxide in four places in human body. Use the information given in the tables to describe the process of exchange between the oxygenated blood and respiring tissue.

It is given that the partial pressure of oxygen (PO 2 ) in the tissue fluid is 5.3 while the same in the oxygenated blood inside the blood capillaries surrounding them is 13.3. The exchange of gases across the respiratory surfaces takes place by the process of diffusion. The gases always diffuse from a region of high partial pressure to the region of low partial pressure. Thus, the oxygen will diffuse from the oxygenated blood of capillaries into the tissue fluid. Similarly, the partial pressure of carbon dioxide (PCO 2 ) in the tissue fluid is 6.0 while in the oxygenated blood of capillaries, it is 5.3. Thus, the Co 2 will be diffuse from the tissue fluid of respiring cells to the blood of capillaries surrounding the tissues.

E M B I B E

Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 9 - Gas Exchange>EXAM-STYLE QUESTIONS>Q 6

HARD

AS and A Level

IMPORTANT

Earn 100

The diagram shows two cells from the lining of the trachea.

Describe the role of cell P and Cell R in the gas exchange system.

Important Questions on Gas Exchange

HARD

AS and A Level

IMPORTANT

Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 9 - Gas Exchange>EXAM-STYLE QUESTIONS>Q 7

Copy and complete the table to compare the trachea with a respiratory bronchiole. Use a tick (v) to indicate that the structure is present and a cross (x) to indicate that it is not.