membrane

[mem-breyn]

noun

1. Anatomy.,  a thin, pliable sheet or layer of animal or vegetable tissue, serving to line an organ, connect parts, etc.

2. Cell Biology.,  the thin, limiting covering of a cell or cell part.

membrane

/ ˈmɛmbreɪn /

noun

1. any thin pliable sheet of material

2. a pliable sheetlike usually fibrous tissue that covers, lines, or connects plant and animal organs or cells

3. biology a double layer of lipid, containing some proteins, that surrounds biological cells and some of their internal structures

4. physics a two-dimensional entity postulated as a fundamental constituent of matter in superstring theories of particle physics

5. a skin of parchment forming part of a roll

membrane

1. A thin, flexible layer of tissue that covers, lines, separates, or connects cells or parts of an organism. Membranes are usually made of layers of phospholipids containing suspended protein molecules and are permeable to water and fat-soluble substances.

2. See cell membrane

3. Chemistry,  A thin sheet of natural or synthetic material that is permeable to substances in solution.

Other Word Forms

• membraneless adjective
• intermembrane adjective

Word History and Origins

Origin of membrane¹

1375–1425; late Middle English; Middle English membraan parchment < Latin membrāna. See member, -an

Word History and Origins

Origin of membrane¹

C16: from Latin membrāna skin covering a part of the body, from membrum _member

Example Sentences

The model reproduces fine details of neuron structure, synapse activity, and electrical signaling across cell membranes.

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In humans, they are essential for immune defense, while in bacteria they often act as toxins that puncture cell membranes.

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The global constraint principle explains that when one limiting factor -- such as a nutrient -- is alleviated, other constraints like enzyme production, cell volume, or membrane space begin to take over.

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Many are involved in shielding proteins, membranes, and photosynthetic machinery from damage.

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Recognition proteins on the membrane's surface then signal lysosomal enzymes to begin breaking down and removing damaged material.

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Related Words

• sheath 
• sheet