The cell membrane is primarily made up of a mix of lipids and proteins. While lipids assistance to give membranes their flexibility, proteins monitor and sustain the cellís chemical environment and support in the transfer of molecules around the membrane.
Phospholipids are an important component of cell membranes. They form a lipid bilayer where their hydrophillic (attracted to water) head places spontaneously arrange to handle the extracellular fluid and the aqueous cytosol, while their hydrophobic (repelled by water) tail areas face far from the extracellular fluid and cytosol. The lipid bilayer is semi-permeable, permitting only specific molecules to diffuse around the membrane.
Additionally to lipids, membranes are filled with proteins. Actually, proteins account for approximately half the mass of all cellular membranes. A number of these proteins are embedded to the membrane and stick out on either side; these are known as transmembrane proteins.
Both eukaryotic cells, which includes animal cells and plant cells and prokaryotic cells, e.g. bacteria, are surrounded by a cell membrane. A cell membrane is a thin structure that is also referred to as the plasma membrane.
The key functions of the cell membrane are:
To keep up the physical integrity of the cell - that is to mechanically block off the contents of the cell, and also
To handle the movement of particles e.g. ions or molecules, into and out of the cell.
Lists of functions of a cell membrane range from various numbers of functions because particles can move around the membrane in several various ways, such as active transport via membrane pumps, diffusion via ion channels, exocytosis and endocytosis. Some lists count these various transport mechanisms as various functions while other lists count transport of materials as a single function of the cell membrane.
Present in both animal and plant cells, the cell membrane is actually the exterior wall of a cell. In plant cells, it is a 2nd wall and is located just inside the principal cell wall. The cell membranes present in animal cells include a chemical known as cholesterol. This chemical can make the membrane harder. Plant cells do not require cholesterol since they have a cell wall, because of this, their cell membranes are softer.
In order for a cell to stay healthy, the cell has to be able to bring in food and eliminate waste. The cell membrane has tiny doorways or openings. These openings permit the cells to move materials out and in of the cell.Think of your school or home. On the exterior of the building are walls. These walls guard the building from weather and from danger. At different locations on the building are tiny openings that permit people, food, water and electricity to go in. You can find also openings that enable things to leave, such as waste. Without these openings, the building would not be much use.