Oxygen passes through the cell membrane primarily through a process called diffusion. Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration. Since the concentration of oxygen is usually higher outside the cell than inside, oxygen naturally moves into the cell.
The cell membrane is composed of a double layer of phospholipids, which creates a semi-permeable barrier. This means that while it allows certain molecules to pass freely, others cannot. Oxygen, being a small and nonpolar molecule, can easily slip through the lipid bilayer of the membrane without needing any specific transport proteins.
Once inside the cell, oxygen is utilized in cellular respiration, a process that produces energy by metabolizing glucose. This process highlights the importance of oxygen as it not only passes through the membrane effortlessly due to its gas state but also plays a crucial role in energy production vital for the cell’s functions.