The type of transport that usually happens when oxygen is absorbed into cells is diffusion. Oxygen diffuses from the blood into the cells because of the concentration gradient—oxygen concentration is higher in the blood and lower inside the cells. This passive transport requires no energy as oxygen molecules move across the cell membrane into the cells where they are used for cellular respiration.
How oxygen is transported and absorbed:
- Oxygen is carried in the blood primarily bound to hemoglobin inside red blood cells.
- When oxygenated blood reaches tissues, oxygen is released from hemoglobin and diffuses through the thin capillary walls into the tissue cells.
- This movement from blood to cells is via simple diffusion since oxygen travels from an area of higher partial pressure (blood) to lower partial pressure (cells).
Thus, oxygen absorption into cells relies on the passive transport mechanism of diffusion driven by concentration gradients. This is efficient for oxygen delivery to meet cellular metabolic needs.
