Cells have a plasma membrane, also known as the cell membrane. This membrane is a thin, flexible barrier that surrounds the cell and controls what enters and leaves it.

It's important to note that this is not the only type of membrane found in cells. Other important membranes include:

* Nuclear membrane: Surrounds the nucleus of the cell and protects the genetic material (DNA).

* Organelle membranes: Surround organelles like mitochondria, endoplasmic reticulum, and Golgi apparatus, each with specialized functions within the cell.

However, the term "cell membrane" usually refers to the plasma membrane, the outermost boundary of the cell.