Properties of Oxygen

Study Notes

Properties of Oxygen

Most oxygen in the body is bound to heme-containing carrier proteins: myoglobin (Mb) and hemoglobin (Hb).
Photosynthetic organisms contribute to Earth's atmospheric oxygen by releasing diatomic oxygen, maintaining a current level of 21% in the air.
Dalton's law explains that in gas mixtures, each gas contributes to a specific partial pressure directly proportional to its concentration.
The partial pressure of a gas is commonly used to measure its concentration in physiological fluids.
At sea level (760 mm Hg), the partial pressure of oxygen (Po2) is approximately 160 mm Hg (21% of total pressure).
The amount of O2 dissolved in solution is proportional to its partial pressure; Po2 in arterial blood (37°C, pH 7.4) is 100 mm Hg, yielding a concentration of 0.13 mmol/L.
This dissolved O2 concentration of 0.13 mmol/L is insufficient for efficient aerobic metabolism.
Most oxygen transport in blood and muscle storage is facilitated by hemoglobin and myoglobin, complexed with ferrous iron (Fe2+).
Hemoglobin is a tetrameric protein with four heme groups, allowing it to bind four molecules of O2.
In arterial blood, with Hb concentration at 150 g/L (2.3 mmol/L) and O2 saturation at 97.4%, the protein-bound O2 concentration is about 8.7 mmol/L.
Protein-bound O2 concentration represents a significant 67-fold increase compared to dissolved O2.
The total oxygen-carrying capacity of arterial blood, combining dissolved and protein-bound forms, reaches 8.8 mmol/L, equating to nearly 200 mL of dissolved oxygen per liter of blood.

Description

Explore the fascinating properties of oxygen, including its role in the human body as a carrier protein and its significance in photosynthesis. This quiz will cover concepts like partial pressure and Dalton's law, providing insights into the behavior of gases in our atmosphere.