What characteristics of the cell membrane determines what goes into the cell and what doesn't?

Answer 1

The cell membrane's selective permeability is primarily determined by its lipid bilayer structure, which consists of phospholipids with hydrophobic tails and hydrophilic heads. This arrangement allows small, nonpolar molecules to pass through easily, while larger or charged molecules require specific transport proteins or channels. Additionally, membrane proteins play crucial roles in facilitating the transport of substances and in signaling, further regulating what enters or exits the cell. Overall, the combination of lipid composition and protein functions governs the cell's interactions with its environment.