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Role of cell membrane essay
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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 proteins associated with the membrane are not fixed in regular positions. This model has yet to be disproved and will therefore be the basis of this essay.
The lipid component.
Lipid and protein are the two predominant components of the biological membrane. There are a variety of lipids found in membranes, the majority of which are phospholipids. The phosphate head of a lipid molecule is hydrophilic, while the long fatty acid tails are hydrophobic. This gives the overall molecule an amphipathic nature.
In life, it is critical to understand what substances can permeate the cell membrane. This is important because the substances that are able to permeate the cell membrane can be necessary for the cell to function. Likewise, it is important to have a semi-permeable membrane in the cell due to the fact that it can help guard against harmful items that want to enter the cell. In addition, it is critical to understand how water moves through the cell through osmosis because if solute concentration is unregulated, net osmosis can occur outside or inside the cell, causing issues such as plasmolysis and cytolysis. The plasma membrane of a cell can be modeled various ways, but dialysis tubing is especially helpful to model what substances will diffuse or be transported out of a cell membrane. The experiment seeks to expose what substances would be permeable to the cell membrane through the use of dialysis tubing, starch, glucose, salt, and various solute indicators. However, before analyzing which of the solutes (starch, glucose, and salt) is likely to pass through the membrane, it is critical to understand how the dialysis tubing compares to the cell membrane.
1972 fluid mosaic model. Lipids are commonly recognized as fats, oils, wax, etc. There are three
...tible to oxidative stress due to the high concentration of phospholipids, mitochondria rich axoplasm and weak cellular antioxidant protection in them.
Homeostasis is essential to the cell’s survival. The cell membrane is responsible for homeostasis. The membrane has a selective permeability which means what moves in and out of the cell is regulated. Amino acids, sugars, oxygen, sodium, and potassium are examples of substances that enter the cell. Waste products and carbon dioxide are removed from the cell.
The naturally occurring hormone Erythropoietin is primarily found in the kidneys and liver and is used to regenerate red blood cells found in red bone marrow(Heuberger et al. 2013). As red blood cells have no nucleus or cellular components they only have a short lifespan of around 120 days before Erythropoietin is required to regenerate more using the process Erthropoiesis(Heuberger et al. 2013). Erythropoietin also has uses in protecting neural activity and the blood brain barrier(Noguchi et al. 2007) however these factors will not be discussed in this essay.
The mitochondria has an eggshape structure. The mitochondria consists of an inner and outer membrane. The outer membrane is what shapes the organelle to its egglike shape. The inner membrane which folds inward makes a set of "shelves" or cristae that allow the reactions of the mitochondria to take place. The more the mitochondria makes these reactions the more the inner membrane folds.
Its ability to inhibit sodium channels within brain cells thereby protecting the cells from hypoxia (lack of oxygen)
In this discussion post, I'll discuss how the structure of the epidermis and dermis contribute to their functions. I'll also describe all the structures of each and describe how each structure contributes to the function of their respective tissue layer.
(Marieb, 2016). Myelin is the protective coat surrounding and insulating the nerve fibers of CNS. Myelin is fatty tissue substance that if attacked by immune cells causing a short-circuits in the current so that the successive gaps are excited more and more slowly, and eventually impulse conduction ceases which resulted in various forms of symptoms (Marieb, 2016). The degradation could either be “by inflammation, stroke, immune disorder, metabolic disorders, or nutritional deficiencies” (Slomski, 2005). The target that immune cells are sensitized to attack remains
Research Updates. University of Rochester Medical Center. November 10, 2008. National Institutes of Health. February 6, 2009. < http://www.urmc.rochester.edu/neurology/nih-registry/research/index.cfm>.
The normal hemoglobin count for women is between 12.0 to 15.5 grams per deciliter (Chen, Zieve, 2012). The lab tests done for Ms. A. shows her hemoglobin count is only 8 grams per deciliter. This is very low compared to the normal value. Moreover, the normal hematocrit level is between 36 and 46 percent (Chen, Zieve, 2012).
Available from: http://www.ncbi.nlm.nih.gov/pubmed/10459279.
Red blood cell indices:(mean corpuscular volume [MCV], mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration [MCHC]
(Kuhn 2006 and silveri 2006) says that myelin is the fat tissue which forms around axons and speeds the neurotransmission which can enable the better communication with other regions