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The content of the cell, inside the cell membrane, is composed of numerous membrane-bound organelles, which contribute to the overall function of the cell. The origin, structure, and function of each organelle leads to a large variation in the cell composition due to the individual uniqueness associated with each organelle.
Embedded in the membrane are proteins that perform the functions of the plasma membrane. The plasma membrane is not a fixed or rigid structure, the molecules that compose the membrane are capable of lateral movement. This movement and the multiple components of the membrane are why it is referred to as a fluid mosaic.
Fluid mosaic model of a cell membrane. The fluid mosaic model explains various characteristics regarding the structure of functional cell membranes.According to this biological model, there is a lipid bilayer (two molecules thick layer consisting primarily of amphipathic phospholipids) in which protein molecules are embedded.
The inner nuclear membrane encloses the nucleoplasm, and is covered by the nuclear lamina, a mesh of intermediate filaments which stabilizes the nuclear membrane as well as being involved in chromatin function. [9] It is connected to the outer membrane by nuclear pores which penetrate the membranes.
Cross-sectional view of the structures that can be formed by phospholipids in an aqueous solution. A biological membrane, biomembrane or cell membrane is a selectively permeable membrane that separates the interior of a cell from the external environment or creates intracellular compartments by serving as a boundary between one part of the cell and another.
The movement of phospholipids, even those located in the outer leaflet of the membrane, is regulated by the actin-based membrane skeleton meshwork.Which is surprising, because the membrane skeleton is located on the cytoplasmic surface of the plasma membrane, and cannot directly interact with the phospholipids located in the outer leaflet of the plasma membrane.
In animals, the plasma membrane is the outer boundary of the cell, while in plants and prokaryotes it is usually covered by a cell wall. This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of phospholipids, which are amphiphilic (partly hydrophobic and partly hydrophilic).
[13] [16] Detergents can be used to render membrane proteins water-soluble, but these can also alter protein structure and function. [13] Making membrane proteins water-soluble can also be achieved through engineering the protein sequence, replacing selected hydrophobic amino acids with hydrophilic ones, taking great care to maintain secondary ...