The cell membrane of a red blood cell will allow water , carbon dioxide, oxygen and glucose to pass through. Because other substances are blocked from entering, this membrane is called selectively permeable or semipermeable.
The cell membrane of a red blood cell is selectively permeable, also referred to as semipermeable, meaning it allows certain substances to pass through while blocking others. This property is crucial for maintaining the cell's internal environment and regulating the exchange of essential molecules. Water, carbon dioxide, oxygen, and glucose are among the substances that can traverse the cell membrane due to their relatively small size or specific transport mechanisms.
The membrane achieves this selectivity through various structures, including phospholipid bilayers and proteins, which control the passage of molecules based on size, charge, and solubility. This selective permeability is essential for red blood cells to carry out their functions, such as gas exchange and nutrient transport, while preventing the entry of potentially harmful substances. The term "semipermeable" underscores the membrane's ability to permit the passage of certain substances while restricting others, ensuring the cell's integrity and functionality in its dynamic cellular environment.