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Biology vocabulary · Cells and Levels of Organization

Cell membrane

Meaning in biology, with examples

/ˈsel ˌmembreɪn/nounCore term

In biology, cell membrane means: The thin, flexible layer that surrounds every cell and controls what enters and leaves it. It is built mainly from a double layer of phospholipids with proteins set into it.

In Turkish: hücre zarı, plazma zarı

How it is used

Also called the plasma membrane, especially in cell biology and biochemistry. It is described as selectively permeable, and textbooks explain its structure with the fluid mosaic model. Do not confuse it with the cell wall, which lies outside the membrane in plants, fungi and bacteria.

Example sentences

  1. Oxygen and carbon dioxide cross the cell membrane by simple diffusion.

  2. The detergent in the lysis buffer breaks open the cell membrane.

Common collocations

  • plasma membrane
  • selectively permeable membrane
  • membrane protein
  • cross the membrane
  • phospholipid bilayer
  • cellThe smallest unit of life that can survive on its own. Every living thing is made of one or more cells, and each cell is surrounded by a membrane.
  • cell wallA strong, rigid layer outside the cell membrane that supports and protects the cell. Plants, fungi and most bacteria have cell walls, but animal cells do not.
  • diffusionThe net movement of particles from an area where they are more concentrated to an area where they are less concentrated, without the cell using energy.
  • osmosisThe movement of water across a selectively permeable membrane from a dilute solution into a more concentrated one, until the concentrations become more equal.
  • lipidA fatty or oily organic molecule that does not dissolve in water, such as a fat, oil, phospholipid or steroid. Lipids store energy and form cell membranes.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Cells and Levels of Organization

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