plasma membrane

American  

noun

Cell Biology.

1. cell membrane.

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plasma membrane Scientific  

1. See cell membrane

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Usage

What is a plasma membrane? Plasma membrane is another term for the cell membrane—the thin layer that encloses a cell’s cytoplasm, which is the substance between the membrane and the nucleus. It allows beneficial things to pass through while blocking harmful ones. The cell is the basic structural unit of all living organisms. It is a microscopic structure consisting of a nucleus surrounded by the cytoplasm and enclosed by a membrane—the plasma membrane. In general, a membrane is a thin barrier or covering. In the context of biology, plasma is used as another word for cytoplasm. The membrane consists of a double layer made up of lipid molecules and large protein molecules. Lipids and proteins are the basic building blocks of living cells. They move fluidly in the plasma membrane and function like a system of gates, giving the membrane its ability to allow molecules to pass through. For this reason, the membrane is described as semipermeable (meaning it is capable of allowing things to pass through it). Plants cells also have a rigid outer wall in addition to a plasma membrane. The plasma membrane is also called the plasmalemma.

Etymology

Origin of plasma membrane

First recorded in 1895–1900

Compare meaning

How does plasma-membrane compare to similar and commonly confused words? Explore the most common comparisons:

• plasma membrane vs. cell membrane

Example Sentences

Plasma membrane lipids of bacteria are fatty acids, while the plasma membrane lipids of Archaea are phytanyl groups.

From Textbooks • Jun. 9, 2022

Plasma membrane lipids of Bacteria are phytanyl groups, while the plasma membrane lipids of Archaea are fatty acids.

From Textbooks • Jun. 9, 2022

Plasma membrane lipids of Bacteria are fatty acids while those of Archaea are phytanyl groups.

From Textbooks • Jun. 9, 2022