Here are the essential concepts you must grasp in order to answer the question correctly.
Phospholipid Bilayer
The cell membrane is primarily composed of a phospholipid bilayer, which consists of two layers of phospholipids. Each phospholipid has a hydrophilic (water-attracting) 'head' and two hydrophobic (water-repelling) 'tails.' This arrangement creates a semi-permeable membrane that allows selective passage of substances, with the hydrophilic heads facing outward towards the aqueous environment and the hydrophobic tails facing inward, away from water.
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Membrane Proteins
Membrane proteins are integral and peripheral proteins embedded in or associated with the phospholipid bilayer. Integral proteins span the membrane and can function as channels or transporters, while peripheral proteins are attached to the exterior or interior surfaces. These proteins play crucial roles in cell signaling, transport, and maintaining the cell's structural integrity.
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Cholesterol
Cholesterol molecules are interspersed within the phospholipid bilayer, contributing to membrane fluidity and stability. They help maintain the membrane's integrity at varying temperatures by preventing the fatty acid chains of phospholipids from packing too closely together. This fluidity is essential for the proper functioning of membrane proteins and overall cell function.
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