Question

As a molecule of oxygen enters the body and is delivered to the cells, it passes through many structures. Which sequence shows the correct pathway?

Answer 1

Oxygen travels from the lungs to the alveoli, enters the bloodstream by diffusion, binds to hemoglobin in red blood cells, and is then distributed to body cells through the blood. Carbon dioxide is exchanged for oxygen in the capillaries and is carried back to the lungs for exhalation.

Step-by-step explanation:

The sequence showing the correct pathway of an oxygen molecule entering the body and being delivered to the cells is as follows:

1. Oxygen is inhaled into the lungs.
2. It passes through the bronchial tubes.
3. Oxygen then reaches the alveoli, tiny sacs where gas exchange occurs.
4. The oxygen enters the bloodstream via the alveolar-capillary membrane by simple diffusion.
5. Once inside the bloodstream, oxygen binds to hemoglobin in red blood cells.
6. The oxygen-rich blood is carried back to the heart.
7. The heart pumps the oxygenated blood through arteries to the capillaries of various tissues.
8. Oxygen moves from the capillaries into the body cells, while carbon dioxide moves from the cells into the capillaries.
9. Carbon dioxide is carried back to the lungs to be exhaled.

This process ensures that every cell receives the oxygen it requires for cellular respiration, which is crucial for the production of energy within the cell.