Here's why:
* Selective permeability: The cell membrane is selectively permeable, meaning it controls what substances can pass through it.
* Phospholipid bilayer: The cell membrane is made of a phospholipid bilayer. This bilayer has a hydrophobic (water-repelling) core and hydrophilic (water-attracting) heads. This structure helps regulate what passes through.
* Proteins: Embedded within the cell membrane are proteins that act as channels, pumps, and receptors. These proteins facilitate the movement of specific molecules across the membrane.
In summary: The cell membrane acts as a gatekeeper, carefully controlling the passage of substances into and out of the cell, ensuring the cell's proper functioning and survival.
