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Structural Components of the Cell
Membrane
o

Cell membrane/Plasma membrane
➢
➢

a double layer of lipids and proteins that surrounds a cell and
separates the cytoplasm (the cell's contents) from its surroundings
...
It can also regulate the amount of
certain substances that enter and exit the cell
...


Structure of the Cell Membrane
➢ These membranes are typically referred to as phospholipid bi-layers
because they are primarily composed of phospholipids and proteins
...
The mosaic appearance of the cell membrane is due to the
large number of different proteins and lipids present
...
These are
lipid molecules with two nonpolar fatty acid tails and a polar phosphate
group head
...
Other substances, such as proteins, can also bind to the
phospholipid bilayer
...
When phospholipids are in water or an
aqueous solution, which includes the inside of the body, the hydrophilic
heads orient themselves to the outside, while the hydrophobic tails orient
themselves to the inside
...


➢ Except for bacteria and archaea, all organisms' bodies are made up of
eukaryotic cells, which have a nucleus surrounded by a phospholipid
bilayer membrane
...
Cholesterol is an
important sterol that regulates the fluidity of the cell membrane in animal
cells
...
The amount of cholesterol in the

membrane helps to maintain its permeability, allowing the correct
number of molecules to enter the cell at any given time, rather than too
many or too few
...
Proteins
constitute roughly half of the cell membrane
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Some of these proteins are
receptors that bind to signal molecules, while others are ion channels
that are the only way for ions to enter and exit the cell
...
Because of its structural composition, the
cell can carry out its functions

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