Cell membrane - also known as plasma membrane, is a double layer of lipids and proteins that surrounds a cell and separates the cytoplasm (the contents of the cell) from its surrounding environment.
Cell membrane is selectively permeable, which means that it only lets certain molecules enter and exit.
Cell membrane can control the amount of some substances that go into or out of the cell.
All cells have cell membrane
Cell membranes are composed primarily of phospholipids and proteins and are typically described as phospholipid bi-layers
The cell membrane has a fluid consistency due to being made up of large part of phospholipids, and because of this, proteins move freely across its surface
The multitude of different proteins and lipids in the cell membrane give it the look of a mosaic.
Phospholipids - are the main component of cell membranes.
These are lipid molecules made up of a polarphosphategrouphead and twononpolarfattyacidtails.
POLAR PHOSPHATE GROUP HEAD
is hydrophilic which means "water-loving" (attracted)
NONPOLAR FATTY ACID TAILS
are hydrophobic which means "water-hating" (repelled)
The phospholipid bilayer also serve as binding sites for other substances such as proteins
The properties of phospholipid molecules are: hydrophilic, hydrophobic, polar, and non-polar.
These allow molecules to spontaneously form a double-layered membrane
When in water or an aqueous solution, which includes the inside of the body, the hydrophilic heads of phospholipids will orient themselves to be on the outside while the hydrophobic tail will be on the inside
The technical term for the double layer of phospholipids that forms the cell membrane is phospholipid bilayer.
Eukaryotic cells which make up the bodies of all organisms except for bacteria and archaea, also have a nucleus that is surrounded by a phospholipidbilayer membrane
Cell membrane also contains glycolipids and sterols
One important sterol is cholesterol, which regulates the fluidity of the cell membrane in animal cells.
When there is less cholesterol, membranes become more fluid, but also more permeable to molecules
The amount of cholesterol in the membrane helps maintains its permeability so that the right amount of molecules can enter the cell at a time, not too many or too few.
Cell membrane also contains many different proteins.
Trans membrane proteins - proteins that are embedded in the membrane but stick out on both sides
Receptor proteins - proteins that bind to signal molecules and send a signal to the cell
ion channels - are proteins that allow ions into or out of the cell
Cell membrane can also allow the cell to interact with its environment and communicate with other cells.
The cell can perform its roles due to its structural composition
Cell/plasma/cytoplasmic membrane - biological membrane that separates the interior of a cell from its outside environment
The primary function of the cellmembrane is to protect the cell from its surroundings .
Composed of a phospholipidbilayer with embedded proteins, the plasma membrane is selectivelypermeable to ions and organic molecules and regulates the movement of substances in and out of the cells.
Plasma membrane must be very flexible in order to allow certain cells like red blood cells and white blood cells to change shape as they pass through narrowcapillaries.
Plasma membrane also plays a role in anchoring the cytoskeleton to provide shape to the cell and in attaching to the extracellular matrix and other cells to help group cells together to form tissues
It also maintain cells potential
Cell membrane is a thin semi-permeable membrane that surrounds the cytoplasm of a cell
CELL MEMBRANE'S FUNCTION
Protect the integrity of the interior of the cell by allowing certain substances into the cell while keeping other substances out
It serves as a base of attachment for the cytoskeleton in some organisms and the cellwall in others
It helps support and maintain cell shape
CELL MEMBRANE'S FUNCTION
It regulates cell growth through the balance of endocytosis and exocytosis
Endocytosis - lipids and proteins are removed from the cell membrane as substances are internalized
Exocytosis - vesicles containing lipids and proteins fuse with the cell membrane increasing cell size
Animal cells, plant cells, and fungal cells have plasma membrane
Internalorganelles are also encased by membranes
The cell membrane is primarily composed of a mix of proteins and lipids.
Depending on the membrane's location and role in the body, lipids can make up anywhere from 20-80% of the membrane, with the remainder being proteins
Lipids - help give membranes their flexibility.
Proteins - monitor and maintain the cell's chemical climate and assist in the transfer of molecules across the membrane.
CELL MEMBRANE LIPIDS
Phospholipids - are a major component of cell membrane
Lipid Bilayer - is semi-permeable, allowing only certain molecules to diffuse across the membrane.
Phospholipids form a lipidbilayer in which
Their HYDROPHILIC (attracted to water) HEAD areas spontaneously arrange to face the aqueous cytosol and the extracellular fluid
While their HYDROPHOBIC (repelled by water) TAIL areas face away from the cytosol and extracellular fluid.
CELL MEMBRANE LIPIDS
Cholesterol - another lipid component of animal cell membrane, that helps keep cell membrane from becoming stiff by preventing phospholipids from being too closely packed together
Cholesterol molecules - selectively dispersed between membrane phospholipids
Cholesterol is not found in the membranes of plant cells