What is the function of a semi-permeable membrane in cells?

The function of a semi-permeable membrane in cells is to facilitate the selective passage of substances. This characteristic is crucial for maintaining homeostasis within the cell, as it allows certain molecules to enter or exit while restricting others. The semi-permeable nature of the membrane is primarily due to its lipid bilayer structure, which permits the passage of small non-polar molecules and water, while larger or charged molecules require specific transport proteins to cross the membrane.

By selectively allowing substances to move in and out, the semi-permeable membrane plays a critical role in various cellular processes, including nutrient uptake, waste removal, and the regulation of ion concentrations. This selectivity is essential for cellular function and overall organismal health.