What is a cell membrane?
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Q:

What is a cell membrane?

A:

Quick Answer

A cell membrane is a thin layer that acts as a barrier that separates an individual cell or a cellular compartment from other surrounding structures. This dynamic layer plays an essential part in the transport of ions and nutrients.

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Full Answer

A cell membrane is a complex structure made of proteins, phospholipids, cholesterol, carbohydrates and several other compounds, all of which are held in place by non-covalent forces. Each cell membrane component serves one or more essential purposes. For example, the proteins act as pumps, gates or receptors, and the lipids create hydrophobic barriers that keep aqueous compartments separate. Cholesterol increases the strength and flexibility of the membrane while also making it less permeable to aqueous compounds.

The transport across cell membranes is an essential cell function, and it depends on the layered membrane structure and the nature of the molecule to be transported. Some molecules, such as oxygen and glucose, are transported through the membrane without requiring any energy, but ions, such as sodium and potassium, are only transported actively, which means that energy is required. The cell membrane is also capable of expelling part of its contents outside through a process called exocytosis or enveloping external molecules through endocytosis. Other functions of the cell membrane include providing shape to the cell by anchoring the cytoskeleton, maintaining the cell potential and sending molecular signals to other cells.

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Related Questions

  • Q:

    How does temperature affect the cell membrane?

    A:

    According to Clinton Community College, temperature primarily affects the fluidity of a cell membrane, with temperatures that are too low causing it to solidify and temperatures that are too high causing it to become more fluid or even break up. Cell membranes at functional temperatures are relatively viscous liquid bubbles. Their structure is maintained by using a phospholipid bilayer and its inherent hydrophilic and hydrophobic qualities.

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  • Q:

    Where is the cell membrane located?

    A:

    The cell membrane is a semipermeable lipid bilayer that surrounds the cytoplasm of all cells. In animal cells, it is the outermost layer of the cell. In plants, fungi and some bacteria, a cell wall surrounds the cell membrane to form the cell's outermost layer.

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  • Q:

    What keeps cell membrane from collapsing?

    A:

    According to science writer Clare Smith for SeattlePi, the cell membrane is kept from collapsing by its phospholipid bilayer, maintenance of the correct temperature, a cytoskeleton and cell junctions. These are necessary because the cell membrane is one of the most crucial components of a cell.

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  • Q:

    What would happen if there was no cell membrane?

    A:

    The cell membrane is essential to the life of the cell and without it, the cell dies. If all the cells in an organism suddenly die, the organism itself dies as well.

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