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These specific properties allow phospholipids to play an important role in the cell membrane. Their movement can be described by the fluid mosaic model, which describes the membrane as a mosaic of lipid molecules that act as a solvent for all the substances and proteins within it, so proteins and lipid molecules are then free to diffuse ...
In organisms, the cell membrane consists of a phospholipid bilayer. In the bilayer, the phospholipid molecule is movable. These movements are categorized into two types, lateral movements and transverse movements (also called Flip-Flop). The first is the lateral movement, where the phospholipid moves horizontally on the same side of the membrane.
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.
By contrast, the exoplasmic side (the side on the exterior of the cell) consists mainly of phosphatidylcholine and sphingomyelin, a type of sphingolipid. Each glycerophospholipid molecule consists of a small polar head group and two long hydrophobic chains. In the cell membrane, the two layers of phospholipids are arranged as follows:
Illustration of a eukaryotic cell membrane Comparison of a eukaryotic vs. a prokaryotic cell membrane. The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extracellular space).
In a single cycle of the pump, three sodium ions are extruded from and two potassium ions are imported into the cell. Active transport is the movement of a substance across a membrane against its concentration gradient. This is usually to accumulate high concentrations of molecules that a cell needs, such as glucose or amino acids.
Lipid metabolism is the synthesis and degradation of lipids in cells, involving the breakdown and storage of fats for energy and the synthesis of structural and functional lipids, such as those involved in the construction of cell membranes. In animals, these fats are obtained from food and are synthesized by the liver. [1]
Of the phospholipids, the most common headgroup is phosphatidylcholine (PC), accounting for about half the phospholipids in most mammalian cells. [36] PC is a zwitterionic headgroup, as it has a negative charge on the phosphate group and a positive charge on the amine but, because these local charges balance, no net charge. [37]