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What Are The Major Components Of Biological Membranes And How Do They Contribute
| Term Paper Title |
What Are The Major Components Of Biological Membranes And How Do They Contribute |
| # of Words |
2920 |
| # of Pages (250 words per page double spaced) |
11.68 |
What Are The Major Components of Biological Membranes And How Do They Contribute
To Membrane Function?.
What Are The Major Components of Biological Membranes And How Do They Contribute
To Membrane Function?.
Summary.
The role of the biological membrane has proved to be vital in countless
mechanisms necessary to a cells survival. The phospholipid bilayer performs the
simpler functions such as compartmentation, protection and osmoregulation. The
proteins perform a wider range of functions such as extracellular interactions
and metabolic processes. The carbohydrates are found in conjunction with both
the lipids and proteins, and therefore enhance the properties of both. This may
vary from recognition to protection.
Overall the biological membrane is an extensive, self-sealing, fluid,
asymmetric, selectively permeable, compartmental barrier essential for a cell or
organelles correct functioning, and thus its survival.
Introduction.
Biological membranes surround all living cells, and may also be found
surrounding many of an eukaryotes organelles. The membrane is essential to the
survival of a cell due to its diverse range of functions. There are general
functions common to all membranes such as control of permeability, and then
there are specialised functions that depend upon the cell type, such as
conveyance of an action potential in neurones. However, despite the diversity of
function, the structure of membranes is remarkably similar.
All membranes are composed of lipid, protein and carbohydrate, but it is
the ratio of these components that varies. For example the protein component may
be as high as 80% in Erythrocytes, and as low as 18% in myelinated neurones.
Alternately, the lipid component may be as high as 80% in myelinated neurones,
and as low as 15% in skeletal muscle fibres.
The initial model for membrane structure was proposed by Danielli and
Davson in the late 1930s. They suggested that the plasma membrane consisted of a
lipid bilayer coated on both sides by protein. In 1960, Michael Robertson
proposed the Unit Membrane Hypothesis which suggests that all biological
membranes -regardless of location- have a similar basic structure. This has been
confirmed by research techniques. In the 1970s, Singer and Nicholson announced a
modified version of Danielli and Davsons membrane model, which they called the
Fluid Mosaic Model. This suggested that the lipid bilayer supplies the backbone
of the membrane, and pr
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