Customer center

We are a boutique essay service, not a mass production custom writing factory. Let us create a perfect paper for you today!

Example research essay topic: Tay Sachs Disease White Blood Cells - 2,021 words

NOTE: Free essay sample provided on this page should be used for references or sample purposes only. The sample essay is available to anyone, so any direct quoting without mentioning the source will be considered plagiarism by schools, colleges and universities that use plagiarism detection software. To get a completely brand-new, plagiarism-free essay, please use our essay writing service.
One click instant price quote

... would fatally digest itself away. Some of these enzymes break down proteins, others attack fats, and still others disassemble the nucleic acids that make up DNA and RNA (Bourne, 1992, p. 123). Lynosomes don't always work right. When they fail, the result can be catastrophic disease. In Tay-Sachs disease, for example, victims have inherited a faulty gene, which leads to a defective enzyme or no enzyme at all.

As a result certain undigested molecules accumulate in the lysosomes, gradually leading to a kind of lysosomal constipation that makes the organelle swell so big it essentially chokes the nerve cell to death. Before long, so many nerve cells are destroyed that the brain is unable to function normally. In Tay-Sachs disease the disruption of brain function eventually becomes so severe that its victims often die in early childhood. About two dozen other so-called lysosomal storage diseases are known (Bourne, 1992, p. 139). For a proper understanding of cell's work you should know that there is an apparatus within the cell that can detect misshapen or otherwise defective proteins during the manufacturing process, pull them out of production, "melt" the rejects down for their raw materials, and send those back for recycling (Rensberger, 1996, p. 196). Obviously, the life of the cell and the health of the person depend on cells having properly functioning proteins.

It is even conceivable that without such a quality control program, life could not have evolved much beyond the one-celled stage. The first stage of the quality control process happens within the ER. One of the best-studied examples involves a very complex receptor protein that is essential to the immune system. It is manufactured by the white blood cells called T cells and does its job as a receptor in the T cell's outer membrane.

The receptor is a modular protein made of seven different smaller proteins. Each of those seven is the product not just of different exons but of different genes, and in some cases the genes are even on different chromosomes. So to make the receptor, seven ribosomes must manufacture seven amino acid chains, injecting each one independently into the ER. Inside the ER the chains must find one another and lock together into the right configuration.

The result, as in other receptors, has three regions: one that sticks out of the cell to meet the molecule to be received; a hydrophobic region that passes through the cell membrane, keeping the receptor properly anchored in it; and a region that sticks into the cell to carry out the appropriate response when the outer portion receives the right molecule (Rensberger, 1996, p. 200). Experiments with cultured T cells show that it takes about thirty minutes for batches of the seven newly made modules to be assembled into complete receptor complexes. Normally these complexes are then shipped from the ER to the Golgi apparatus-yet another processing facility that, in the living-room cell, is represented by the drifting stacks of deflated beanbag chairs. From there the receptors are dispatched outward for installation in the plasma membrane. The experiments also led to a surprising finding - that partially made receptors containing fewer than all seven components almost never are installed in the plasma membrane. In fact, they don't usually even reach the Golgi apparatus, which most cell biologists call simply the Golgi. (It is usually capitalized because it is named for Camillo Golgi, the Italian physician who described the organelle in the late nineteenth century. ) The mistake proteins remain trapped in the ER.

Biologists know the receptors are missing a module because the experiments have been done with cultured cells from which one of the seven genes was removed. If any of the seven component proteins is missing, the others will assemble as far as they can go but the resulting incomplete complex is blocked from exiting the ER (Bourne, 1992, p. 55). So, who does the inspecting? How does the ER decide whether a protein is properly made? One clue has come from the discovery of a protein that resides permanently inside the ER and which binds to certain newly made amino acid chains before they can fold.

It is called, prosaically, binding protein, or BiP, which is, of course, pronounced bip. Researchers have found that in some cases BiP binds to an unfolded protein while it is being injected into the ER but then breaks away as the protein achieves its fully folded form. It looks as if BiP is not terribly choosy about the proteins it binds to, but always binding to any region of a protein that is hydrophobic, or water repelling. Many proteins contain such regions, but when the amino acid chain is completely folded, the hydrophobic region is supposed to lie buried deep inside the overall configuration, in a position where other molecules can't "see" it.

The outer faces of most proteins are, by contrast, hydrophilic, or water-loving (Bourne, 1992, p. 64). So how would BiP keep an unfolded or improperly folded protein in the ER? Possibly because its own amino acid sequence has a tail (the head binds to the newly made proteins) that sticks to some receptor facing the inside of the ER. Some researchers have speculated that this is the case because of a curious similarity among BiP and several other proteins known to be permanent residents of the ER. They all have tails composed of the following sequence of four amino acids: lysine-aspartic acid glutamic acid-leucine. This similarity suggests a similar function for the sequence, and since all the proteins that have this sequence stay in the ER, it is simply a logical guess that the function could be to anchor BiP somehow to the inside face of the ER (Bourne, 1992, p. 77).

Upon reaching the Golgi, a protein sticking out of the vesicle's surface interacts with others protruding from the Golgi. If they fit together, the vesicle has found the right destination and, after some further interaction between molecules on the surfaces, the membranes of vesicle and Golgi fuse, automatically dumping the cargo of partially processed proteins into the Golgi. Somewhere in this sequence of events, the protein cage fell away (Fausto-Sterling 2003, p. 37). Thus, the Golgi apparatus is a kind of assembly line that receives proteins from the ER, which may already have fastened fats to them at various points, and processes them further, one step at a time.

The Golgi typically consists of four to six chambers. The protein gets modified in one chamber - some of the carbohydrate chains, for example, may be trimmed or remodeled - and then sent to the next chamber for further processing. The goal is to modify each protein as necessary to suit its function and then sort the proteins by type and by destination, either in the cell membrane or outside the cell. There is evidence that the Golgi, like the ER, has its own quality control program. If, for example, the seven-module T- cell receptor is made so that it lacks either of a certain two of the modules, the complexes do get shipped from the ER to the Golgi, but there they are blocked. A faulty protein complex may slip past the ER's inspectors, but the Golgi has a backup system for catching mistakes (Fausto-Sterling 2003, p. 80).

Now, at last, I want to explain you another kind of "protecting" process. You should understand that in every moment of every day, every person's body is a battleground where microscopic aggressors constantly seek their biological destiny to multiply and be fruitful. Most of the time, of course, most people remain healthy because their bodies are able to repel the invaders or, at least, to keep them under control. The defenders are the cells of the immune system, the part of the body that, except for the brain, is probably the most complex and least understood. It is not a single organ like the liver or the brain. It is a diffuse system made up of many discrete structures, including the bone marrow, the spleen, the thymus gland, and the lymph nodes, and of many different kinds of free-roaming, independent blood cells called lymphocytes.

These are small, round, featureless "white blood cells. " Cells of the immune system are spawned in the bone marrow and some receive further rearing in the thymus, but from there they fan out to inhabit every part of the body except the brain. The immune system as a whole is fabulously complex, a Byzantine array of many cell types with varying powers, each responding to different stimuli but often unable to function except in alliances with various other cell types within the immune system. Most attempts to explain the immune system in the popular press - a favorite metaphor is the military with its layers of command and various types of hardware - fall short. Still, the fundamentals are actually not so hard to grasp if they are considered one part at a time. The body's first line of defense is its skin and the membranes lining such exposed surfaces as those in the nose and throat. Few microbes can penetrate intact skin, and because its outermost layer is dead anyway, its cells are not vulnerable.

Tiny glands in the skin - sweat glands, tear glands, and the sebaceous glands - all secrete antimicrobial chemicals. So do the cells that produce saliva and mucus in the nose, mouth, and throat. In ways that are not fully understood, these cells secrete natural antibiotics that kill bacteria or, at least, block their reproduction (Singer, 1979, p. 62). Within the lungs a more active defense is provided by macrophages, those "big eater" cells that roam the body like hungry amoebas. All kinds of noxious particles, alive and dead, are inhaled into the lungs with every breath. Many stick to the wet surfaces of the tiny air sacs within the sponge like lung.

Lurking on the same wet surfaces, however, are macrophages of a type called dust cells, which eat almost any debris they encounter. Enzymes from the dust cell's lysosomes digest most of the bacteria and other organic materials, but if the voracious cell swallows something indigestible, it simply stores it in a large vesicle, or vacuole - a kind of internal waste basket. Eventually, when the dust cell gets full and can choke down no more, it seems to know its career is finished. The cell crawls up through the airways, out of the lung and into the windpipe, hauling its indigestible cargo, until the windpipe joins the gullet, which leads down to the stomach. The dust cell is swallowed and digested. Even stomach acid can be considered a defense mechanism because it kills not just dust cells but most swallowed bacteria (Rensberger, 1996, p. 279).

The respiratory system also has a mechanism to rid itself of things that dust cells do not carry out, such as inhaled particles and excess mucus. Lining the windpipe and connecting airways are cells with hairlike cilia that reach into the passageway. The cilia beat in coordinated waves, like the ones that carry the egg in the fallopian tube, moving the unwanted substances up to the gullet and, like the stuffed dust cells, into the gullet (Rensberger, 1996, p. 272). Though not often considered formal parts of the immune system, all these processes are obviously of major importance in protecting the living cells inside the body.

References Bourne, G. H. (1992). Division of Labor in Cells. New York: Academic Press. Fausto-Sterling, A. (2003). The Problems of Biology.

In Debating Biology: Sociological Reflections on Health, Medicine, and Society, Williams, S. J. , Bike, L. , & Bendelow, G. A. (Eds. ) (pp. 123 - 131). New York: Routledge. Pines, M. (1998). Inside the Cell: The New Frontier of Medical Science.

Bethesda, MD: US Dept. of Health Education, and Welfare, Pubic Health Service. Rensberger, B. (1996). Life Itself: Exploring the Realm of the Living Cell. New York: Oxford University Press. Singer, C. (1979).

A History of Biology to about the Year 1900: A General Introduction to the Study of Living Things (3 rd Rev. ed. ). London: Abelard-Schuman.


Free research essays on topics related to: amino acid, white blood cells, part of the body, tay sachs disease, golgi apparatus

Research essay sample on Tay Sachs Disease White Blood Cells

Writing service prices per page

  • $18.85 - in 14 days
  • $19.95 - in 3 days
  • $23.95 - within 48 hours
  • $26.95 - within 24 hours
  • $29.95 - within 12 hours
  • $34.95 - within 6 hours
  • $39.95 - within 3 hours
  • Calculate total price

Our guarantee

  • 100% money back guarantee
  • plagiarism-free authentic works
  • completely confidential service
  • timely revisions until completely satisfied
  • 24/7 customer support
  • payments protected by PayPal

Secure payment

With EssayChief you get

  • Strict plagiarism detection regulations
  • 300+ words per page
  • Times New Roman font 12 pts, double-spaced
  • FREE abstract, outline, bibliography
  • Money back guarantee for missed deadline
  • Round-the-clock customer support
  • Complete anonymity of all our clients
  • Custom essays
  • Writing service

EssayChief can handle your

  • essays, term papers
  • book and movie reports
  • Power Point presentations
  • annotated bibliographies
  • theses, dissertations
  • exam preparations
  • editing and proofreading of your texts
  • academic ghostwriting of any kind

Free essay samples

Browse essays by topic:

Stay with EssayChief! We offer 10% discount to all our return customers. Once you place your order you will receive an email with the password. You can use this password for unlimited period and you can share it with your friends!

Academic ghostwriting

About us

© 2002-2024 EssayChief.com