Friday, January 31, 2020
The Plama Membrane Essay Example for Free
The Plama Membrane Essay The plasma membrane exists in all living things for the simple reason that it serves vital functions without which the cell cannot survive.            The plasma membrane is composed primarily of a phospholipid bilayer which is made up of hydrophobic lipid â€Å"tails†that point inwards and hydrophilic phosphate â€Å"heads†that are positioned so that one layer is in contact with the extracellular fluid and the other with the cytosol. The membrane may thus be thought of as the cells â€Å"skin†enclosing and protecting the organelles and the nucleus. The cell (and its components) however, is not cut off from its environment because the plasma membrane is semipermeable, allowing specific substances necessary for the normal functioning of the cell to pass through. Also, embedded in the bilayer are proteins that assist the passage of substances that normally would not be able to pass through by simple diffusion. A good example would be the sodium-potassium pump (Krogh, 2003) which is responsible for the active transport of these ions. Both potassium and sodium need to move up their concentration gradients (into and out of the cell, respectively) and since both are ions that would be difficult to transport through the hydrophobic interior of the bilayer, such transport needs to be facilitated by the use of proteins that will serve as channels through which these ions can pass through. This therefore illustrates as well the regulatory functions of the plasma membrane in that it allows transport into and out of the cell in a selective manner (Postlethwait Hopson, 2006).            Proteins that lie on the surface of the plasma membrane also serve a role in facilitating communication between the cell and its environment, including other cells. Lymphocytes (white blood cells) for example, differentiate foreign cells from that of the body by recognizing antigens, surface-bound proteins that serve as identification for the lymphocyte to know whether the other cell is an invader that needs to be eliminated (Postlethwait Hopson, 2006).            Clearly, the plasma membrane serves critical roles in cellular function, not just in THE PLASMA MEMBRANE                                                                                                                                                   Page # 2 protecting the cell but as well as in transport, regulation and communication, and since, as Krogh (2003) has stated, â€Å"all life is made of cells†, it follows that life simply is not possible without the plasma membrane. References: Krogh, D. (2003). Biology: A Guide to the Natural World, 3rd ed. Companion Website. Retrieved Dec. 31, 2007, from http://wps.prenhall.com/esm_krogh_biology_3/ Postlethwait, J. H., Hopson, J. L. (2006). Modern Biology.                                          Texas: Holt, Rinehart and Winston.
Thursday, January 23, 2020
Benefits of Cloning vs. Antiquated Religious Beliefs Essay -- Argument
Benefits of Cloning vs. Antiquated Religious Beliefs    When one thinks of cloning, what comes to mind? Movies such as "Multiplicity" can give the lay person a very distorted image of cloning. In this particular movie, actor Michael Keaton plays a father who cannot handle his crazily busy lifestyle. In an effort to be the perfect father, husband and employee, he has himself cloned fairly easily at a nearby medical center. The three clones each have their own personality: one is sarcastic and bitter, one is sweet and sensitive and one is a half-wit- but all are identical. This cloning process is completely false. At this time, scientists have cloned animals including Rhesus monkeys, mice and probably the biggest breakthrough: sheep. Cloning could mean hope for so many different diseases. The advancement of cloning in a medical laboratory should be encouraged. Cloning could save transplant candidates. According to Larry Reibstein and Gregory Beals, companies such as Alexion Pharmaceutical are already beginning to experiment with ways to grow hearts and kidneys in pigs that will not be rejected in transplants (58). Perhaps another reason to encourage cloning is for the treatment of spinal cord injuries. Cloning could give hope to couples unable to have children of their own. By advocating cloning, doctors may find a way to cure or even prevent genetic diseases. Perhaps, though, the most important reason to advance cloning in the laboratory is to treat leukemia's and cancers. Very possibly, through cloning and genetic engineering, the growth of poorly formed cells could be stopped immediately.   One reason to clone is hope for organ transplants. Currently organ transplantation is considered by some to ... ...sweek. 18 May 1998. Cohen, P. "Dolly Helps the Infertile. World Wide Web. AOL 19 May 1999 [www.newscientist.com] "Human Cloning." World Wide Web. AOL. 24 Apr 1999. [www.humancloning.org/] Masci, David. "The Cloning Controversy." The CQ Researcher. 9 May 1997: 409-431. Mikos, Antonios G. & Mooney, David J. "Growing New Organs." World Wide  Web. AOL. 17 May 1999. [www.sciam.com/1999/0499issue/0499mooney.html] "New scientist." World Wide Web. AOL 25 Apr 1999. [www.newscientist.com/nsplus/insight/clone.html] Ostrander, E. "Seattle Researchers Zero In On Location of Gene For Inherited Prostate Cancer..." World Wide Web. AOL. 23 May 1999. "Spinal Cord Repair." World Wide Web. AOL. 19 May 1999. [www.sciam.com/explorations/081897spinal/zacks.html] Woodward, Kenneth L. "Today the Sheep..." Newsweek 10 Mar 1997: 60.
Wednesday, January 15, 2020
Britannica online Essay
This is a book proposal that has been created to ensure the children of today are still exposed to the same childhood experiences that we all had years ago. In today’s society we are much more fast paced and immediately are drawn to electronics such as computers, television, movies, ipods, etc†¦ The numbing effect of this constant barrage of information on very young children could lead to a sort of deterioration of values in a small child. Proposed title: Back to the Basics: A Collection of Nursery Rhymes for Today’s Child Introduction: Many of us picked up our own sets of values and morals from what had been passed down to us through tradition. A Nursery Rhyme is a poem or a song, traditionally taught to very young children. Nursery Rhymes in the English language are usually British in origin, dating back to as far as the 16th Century. Aside from the ones imported from England, many Nursery Rhymes also developed in North America (Encyclopedia Britannica online, 2008). These little songs and poems form a sort of symbolic â€Å"backbone†to the continuing cultural and psychological development of the American people and culture. Indeed, at its very core, a Nursery Rhyme is a sort of cultural footprint. While most oral tradition (ex: nursery rhymes) may sound more like nonsense or oversimplified, moralistic tales set to a rhythm and a tune, they carry the symbolic weight of generations past (Bettelheim, 1976). Passed on through tradition and brought alive by the imaginations of the very children who hear them and pass them on, these rhymes bear the values of the culture that created it. For example, Humpty Dumpty’s story reminds us that there are some things that, once broken, can never be mended. In another example, the Itsy Bitsy Spider speaks to us of the value of perseverance. Sometimes, a Nursery Rhyme isn’t just a moral legacy, but a historical one as well: showing us how people lived or worked during the particular time when these rhymes were created. For example, while shepherding may no longer be a common profession, especially in heavily populated urban areas, even children from the inner city are aware that it was once a way of life, thanks to Little Bo Peep and her sheep. Rationale: Nursery Rhymes have been in existence for hundreds of years, but what exactly is the importance in continuing in this tradition? Children are automatically drawn into these stories because of the rhyme, there is rhythm, and they are often about creatures in otherwise unimaginable circumstances, which leads the child’s own imagination to wander. In addition to being an effective vehicle through which a culture propagates and preserves itself, Nursery Rhymes are of particular importance in the development of a young child’s growing language and memory skills. There is a reason that today, even after growing up; we can still remember these little phrases. They have made great impact in our childhood learning schemata and we believe that if they continue to be reintroduced to the children of today, their impact would be highly beneficial. We believe that this book will be a great hit among small children and their parents, and that with the aid of colorful illustrations, this book can be very useful in promoting a child’s mental, psychological, and social development. Methodology: After much deliberation, we decided to limit our selection to the most common and well-loved Nursery Rhymes. We looked through several collections of nursery rhymes, both online and offline, and picked out the ones that occurred the most frequently. Given that we plan to make this book a children’s book, we limited our selection to only four Nursery Rhymes. We chose to do this so that the book could accommodate the illustrations that we hope will be included as visual aids for the children, without being too heavy or cumbersome for even a small child to read and carry. These Nursery Rhymes are as follows: Humpty Dumpty: Humpty Dumpty sat on a wall, Humpty Dumpty had a great fall. All the king’s horses, and all the king’s men, Couldn’t Put Humpty together again. Jack and Jill Jack and Jill went up the hill, To fetch a pail of water. Jack fell down and broke his crown. And Jill came tumbling after The Itsy Bitsy Spider The Itsy Bitsy Spider Climbed up the water spout. Down came the rain And washed the spider out. Out came the sun And dried up all the rain, And the itsy bitsy spider Climbed up the spout again. Little Bo Peep Little Bo-Peep has lost her sheep, And can’t tell where to find them. Leave them alone, And they’ll come home, Wagging their tails behind them. Thank you very much for taking the time to read and consider this. We look forward to your timely and positive reply! References Bettelheim, Bruno (1976). Uses of Enchantment: the Importance of Fairy Tales. New York: Knopf Encyclopedia Britannica online, concise version. Nursery Rhymes. retrieved February 3 2008. from http://www. britannica. com/ebc/article-9373775
Monday, January 6, 2020
Beloved Essay - 3346 Words
Beloved Essay In today’s modernized world, it is crucial to be able to comprehend and recognize conflicts dealing with racial tensions due to the increased growth of diversity in nations all over the world. Countries like North America are inhabited by people of different backgrounds, cultures, and colors. Since there is intermingling among everyone, the differences between the diverse ethnic backgrounds could stir up trouble which can lead to serious skirmishes like Watts Rebellion in 1965. To prevent and weaken the strength of racial tension, the citizens of the United States must be educated about racial problems before being released into the real world. The best approach towards racial equity begins in the classroom and through†¦show more content†¦Painted across the pedestal he knelt on were the words ‘At Yo Service’†(300) Even though the Bodwins are helping Denver find a job, having a statue of a black boy erected in their home goes to show the reader how hypocritical the Bodwins were in that they did not see African Americans as true equals to whites. Especially with the phrase â€Å"at yo service,†it implies that the Black boy statue represents Blacks are those who are always serving; if the Bodwins really wanted to help abolish slavery and move closer to racial equity, they would not have had that degrading statue in the first place. The second standard of Critical Race Theory is Interest Convergence. Interest Convergence is defined as an illusory â€Å"improvement†towards racial equity which means that those who helped the African Americans did not do so out of pure kindness, but because of other motives that were fueled by selfish intentions. In the beginning of Beloved, an instance of interest convergence appears when Mr. Garner brags about his slaves on Sweet Home plantation. â €Å"‘Y’all got boys,’ he told them. ‘Young boys, old boys, picky boys, stroppin’ boys. Now at Sweet Home, my niggers is men every one of em. Bought em thataway, raised em thatway. Men every one’†(12). By bragging about his slaves, Mr. Garner fools his slaves into thinking that he is bragging because he is genuinely proud of his slaves; however, Mr. Garner’s true intention for bragging about his laid-back treatment forShow MoreRelated Beloved Essay593 Words  | 3 Pages Beloved, like many of the other books we have read, has to deal with the theme of isolation. 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