Oxygen plays a crucial role in the human body primarily through aerobic respiration, which is essential for ATP production in mitochondria. Beyond respiration, oxygen is also involved in the synthesis of proteins, particularly collagen, which requires oxygen for the enzymatic conversion of proline to hydroxyproline. This process is vital for the maturation of collagen, a key structural protein. Additionally, oxygen is a component of various organic molecules, including proteins, carbohydrates, and lipids, derived from the food we consume. While oxygen is necessary for certain biological functions, free elemental oxygen can be harmful, leading to the need for safe transport within the body, typically bound to hemoglobin. Some therapies utilize high oxygen environments, but their effectiveness and safety can be controversial. Furthermore, certain organisms, like anaerobic bacteria, are adversely affected by oxygen, highlighting its dual nature in biological systems. Overall, while the primary use of oxygen is for energy production, it also plays significant roles in the synthesis of essential biomolecules.