cell membrane

noun

plural cell membranes

: a membrane of a cell

especially : a semipermeable limiting layer of cell protoplasm consisting of a fluid phospholipid bilayer with intercalated proteins : plasma membrane

Despite being much maligned in the popular press, cholesterol plays a crucial role in organizing cell membranes and controlling their physical properties.

—Amanda Yarnell

… a cascade of reactions culminating in the transfer of a phosphate group to a protein complex that carries ions across the cell membrane.

—Science News

Examples of cell membrane in a Sentence

Recent Examples on the Web

First observed in a common lab bacterium only 14 years ago, bacterial nanotubes are structures made of cell membrane that allow nutrients and resources to flow between two or more cells. —Veronique Greenwood, Quanta Magazine, 6 Jan. 2025

Blood cholesterol is necessary for good health, helping your body perform important functions such as making hormones (chemical messengers that control many body functions), building cell membranes, and digesting fat.2 Cholesterol from foods is known as dietary cholesterol. —Jamie Johnson, Verywell Health, 2 Jan. 2025

To accomplish this, experts first create extremely tiny holes only a few nanometers wide in the bacteria’s cell membrane. —Andrew Paul, Popular Science, 18 Dec. 2024

The reason is that simulating the brain on a conventional computer requires billions of differential equations coupled together to describe the dynamics of cells and networks: analog processes like the movement of charges across a cell membrane. —IEEE Spectrum, 31 May 2017

Word History

First Known Use

1840, in the meaning defined above

Kids Definition

cell membrane

noun

: a semipermeable outside layer surrounding the contents of a cell

Medical Definition

cell membrane

noun

: a membrane of a cell

especially : plasma membrane