Final answer:
The characteristic of a cell's membrane that allows it to regulate what enters and leaves the cell is called selective permeability. It is important for maintaining homeostasis and ensuring a stable internal environment.
Step-by-step explanation:
The characteristic of a cell's membrane that allows it to regulate what enters and leaves the cell is called selective permeability. The cell membrane is selectively permeable because it has a phospholipid bilayer with embedded proteins that act as gatekeepers. These proteins control the movement of molecules in and out of the cell based on their size, charge, and concentration gradient.
For example, small molecules like oxygen and carbon dioxide can pass through the cell membrane freely through simple diffusion, while larger molecules and ions require specific transport proteins such as channel proteins or carrier proteins to facilitate their movement.
The cell membrane's selective permeability is crucial for maintaining homeostasis and ensuring that the cell's internal environment remains stable and functional.
Learn more about Cell Membrane and Selective Permeability