The Cell - Prokaryotic and Eukaryotic Cells

Life is both wonderful and majestic. Yet for all of its majesty, all organisms are composed of the fundamental unit of life, the cell. The cell is the simplest unit of matter that is alive. From the unicellular bacteria to multicellular animals, the cell is one of the basic organizational principles of biology. Lets look at some of the components of this basic organizer of living organisms. Eukaryotic Cells and Prokaryotic Cells There are two primary types of cells: eukaryotic cells and prokaryotic cells. Eukaryotic cells are called so because they have a true nucleus. The nucleus, which houses DNA, is contained within a membrane and separated from other cellular structures. Prokaryotic cells, however, have no true nucleus. DNA in a prokaryotic cell is not separated from the rest of the cell but coiled up in a region called the nucleoid. Classification As organized in the Three Domain System, prokaryotes include archaeans and bacteria. Eukaryotes include animals, plants, fungi and protists (ex. algae). Typically, eukaryotic cells are more complex and much larger than prokaryotic cells. On average, prokaryotic cells are about 10 times smaller in diameter than eukaryotic cells. Cell Reproduction Eukaryotes grow and reproduce through a process called mitosis. In organisms that also reproduce sexually, the reproductive cells are produced by a type of cell division called meiosis. Most prokaryotes reproduce asexually and some through a process called binary fission. During binary fission, the single DNA molecule replicates and the original cell is divided into two identical daughter cells. Some eukaryotic organisms also reproduce asexually through processes such as budding, regeneration, and parthenogenesis. Cellular Respiration Both eukaryotic and prokaryotic organisms get the energy they need to grow and maintain normal cellular function through cellular respiration. Cellular respiration has three main stages: glycolysis, the citric acid cycle, and electron transport. In eukaryotes, most cellular respiration reactions take place within the mitochondria. In prokaryotes, they occur in the cytoplasm and/or within the cell membrane. Comparing Eukaryotic and Prokaryotic Cells There are also many distinctions between eukaryotic and prokaryotic cell structures. The following table compares the cell organelles and structures found in a typical prokaryotic cell to those found in a typical animal eukaryotic cell. Cell Structure Prokaryotic Cell Typical Animal Eukaryotic Cell Cell Membrane Yes Yes Cell Wall Yes No Centrioles No Yes Chromosomes One long DNA strand Many Cilia or Flagella Yes, simple Yes, complex Endoplasmic Reticulum No Yes (some exceptions) Golgi Complex No Yes Lysosomes No Common Mitochondria No Yes Nucleus No Yes Peroxisomes No Common Ribosomes Yes Yes Eukaryotic and Prokaryotic Cell Structures

Love, Murder, and Jealousy in Shakespeares Macbeth and...

How do Shakespeare and Browning present ideas about love, murder and jealousy in Macbeth, My Last Duchess and The Laboratory? This essay will look at ways William Shakespeare (1564-1616, English actor and playwright) and Robert Browning (1812-1889, English poet and playwright) consider love, murder and jealousy in the play Macbeth and the poems, My Last Duchess and The Laboratory. When comparing these themes it is of interest to consider their historical context and setting. Macbeth was first performed in 1611 and is considered to be one of Shakespeare’s darkest and powerful tragedies. Browning’s poem The Laboratory was also based in the seventeenth century and My Last Duchess in the sixteenth century. Love as depicted in Macbeth and My Last Duchess is not about a conventional sense of love where, for example, boy meets girl but other forms of love. In Macbeth love is described between Macbeth and his wife in terms of â€Å"dearest love† and â€Å"dearest chuck†. Macbeth’s devotion and love for his country finds expression in, â€Å"the service and loyalty I owe†. I n My Last Duchess, however, love appears to be concerned with the extent to which the Duke loves himself, â€Å"I choose/never stoop†. This infers that the Duke views himself in a superior way and would not lower himself to intervene in small annoyances. This is an indication that the Duke is also a selfish man lacking in humility, who puts his own needs and desire for happiness above that of others, including those closest

Animal Farm and Oliver Twist, by George Orwell and Charles Dickens Essay Example For Students

Animal Farm and Oliver Twist, by George Orwell and Charles Dickens Essay Animal Farm and Oliver Twist, by George Orwell and Charles Dickens respectively, are both novels written by two very different authors writing on a rather similar theme. Both novels outline the subject of human suffering and it is the authors different choices of means by which they convey this that creates the immediately apparent contrast. Both writers write their novels in a style new to their era; the awakening of social awareness targeted by Dickens and his contemporary writers of the mid-Victorian period such as Thomas Carlyle and William Morris, and Orwells originality in depicting the fate of Bolshevism in Russia through anthropomorphism. Some have said that Dickenss incentive to write Oliver Twist was that of bellicosity toward a female contemporary of his literary age: Harriet Martineau. Dickens understood fully the propaganda Martineau was incorporating in her novels and aside from the other causes of his writing of Oliver Twist, he wished to disseminate a contrary notion of ill-justice within the infrastructure of industrialist Victorian England. The same can be said of Orwell; he lived amidst the height of British imperialist power and felt that in writing novels on the subject of communism, such as Animal Farm and Nineteen Eighty-four, he could make the others aware of not only the idyllic nature of communism as a working ideological principle, but its ultimate failings when implemented imperfectly. Evelyn Waugh was a writer with whom Orwell shared the style of writing that observed and commented upon politics, and Waugh satirised the nature of bourgeois Britain that Orwell professed to disdain. Unlike Orwell, however, Waugh was a Conservative man. And viewed communism not as a wonderful alternative to capitalism but as an issue that at some point could threaten it. In his book Brideshead Revisited Waugh told of the decline of the aristocracy and thereby predicted a banal future of a classless society. This foresight can be accredited to the nature in which Britain had fought the war; it was a war whereby class mattered little for that brief period in history. Oliver Twist commences its first chapter under the heading: Treats of the place where Oliver Twist was born, and of the circumstances attending his birth. The reader at this stage in his or her knowledge of the books content will not be able to assume a great deal from this and it is possible that one may even incorrectly anticipate a story of a wealthier boy as could have been told by a contemporary of Dickens, such as Martineau. However, any such thoughts are dispelled promptly as the first few introductory paragraphs list instances of suffering on the part of the child being delivered. Dickens may do this to make the novel instantly appeal to those entranced in the type of novel he is writing to oppose, or he may be aiming to begin the book with irony. p. 1 For a long time after it was ushered into this world of sorrow and troubleà ¢Ã¢â€š ¬Ã‚ ¦it remained a matter of doubt whether the child would survive to bear any name at allà ¢Ã¢â€š ¬Ã‚ ¦ Here it can be observed that Dickens chooses to class the child as it, as a means of showing the childs unimportance and insignificance. Immediately the reader can picture the unfortunate circumstances the child has found himself begotten into and the theme of suffering has started. Animal Farm opens immediately into an earnest and simple account of the neglectful nature of a certain Mr. Jones, whom the reader can identify as a farmer. Mr. Jones, of the Manor Farm, had locked the hen-houses for the night but was too drunk to remember to shut the pop-holes. In Animal Farm, the deterioration of the animals lives commences in the aftermath of their revolt against Mr. Jones as they are made to suffer under the auspicious and increasingly powerful pigs. The pigs, as the most intelligent animals on the farm, take over in the role of the negligent farmer and inflict suffering on the animals in the blatant inequality they create. This new way of life contradicts the egalitarianism represented by Animalism which is the revolutions political philosophy Orwell uses to encapsulate communism. It is the degeneration of the animals standard of living that perpetuates the suffering theme surrounding this revolution and the reader is made fully aware of the level of hardship present at the start of the novel during a speech made by the elderly wise boar Old Major. Animal Farm, p. 3 The life of an animal is misery and slavery: that is the plain truth. Animal Farm, p. 4 And you, Clover, where are those four foals you boreà ¢Ã¢â€š ¬Ã‚ ¦? Each was sold at a year old you will never see one of them again Oliver Twist Unlike the excessively intricate language used by Dickens, the language of Orwell is entirely succinct in its use of terminology. The difference between the two narrators is upon first sight obviously that of Dickenss ornate style and Orwells conciseness but also the two authors include irony in different forms to one another. Antigone Jenny Peterson EssayCommunism affected Orwell a great deal and it affected the world equally; in 1980 four in every ten human beings on the earth lived under a Marxist government. Dickens did not have this considerable political monster hanging over his world as communism existed in its infancy at this time; nor did Dickens have a World War engaging around him, and nor did he know of global suffering. The two writers wrote in entirely different ages but were pioneering authors of their respective eras. Suffering continues throughout both Animal Farm and Oliver Twist,not so much as a theme but moreso as an inherent part of the lives of the characters. Orwell scarcely directly mentions the suffering that his characters endure and even when he does he deliberately only skims the surface of that suffering; he chooses never to comment on the lies and propaganda the pigs use in their reign over the animalist farm and merely reports them in the form in which they occur. Dickens, however, ensures that the reader is aware of the message he is conveying by using sarcasm and also on occasion highlighting injustices. Oliver Twist, p. 11 What a noble illustration of the tender laws of England! They let the paupers go to sleep! This quotation serves to demonstrate further the sarcasm Dickens uses in his display of content held against the hierarchy of his society and also the manner in which he points out the suffering to the reader. The reader can also comprehend from this Dickens categorical accusation of the English hierarchy that they are guilty of self-aggrandisement and self-congratulation on a successful and noble society they believe themselves to have achieved. Oliver Twist, p. 222 à ¢Ã¢â€š ¬Ã‚ ¦a weary catalogue of evils and calamities which hard men had brought upon him Oliver. From this, though, one can see also the way in which Dickens also chooses plainly and without irony to raise the readers awareness of the suffering. The novel gains from Dickens mixture of ironical and direct narration a sense of awareness and consciousness in the authorial voice, while the image of the author is continued as that of an intellectually and politically aware person. A reader can draw from a combination of irony and simplicity a feel of knowledge of the text in hand and the subject being narrated on; this is how Dickens manages to achieve an audience of mixed dispositions. Those whom writers such as Harriet Martineau could attract would read Dickens for the epic tales he tells and those interested in the nature of Dickens political writing can also find the novel of interest. Animal Farm, p. 46 Starvation seemed to stare them in the face. Orwell, however, mentions suffering as it would be seen by the animals and not in a more complex way. The animals remain blind to the oppression they endure under the pigs for a long time and never once does the narrator represent events from a biased angle, like the narrator of Oliver Twist does. Dickens narrator is a gentleman aware of the situation and he shows this to his audience; Orwells narrator would not even be associated to a human voice as it expresses no awareness it may have, unlike a human narrator would. In Oliver Twist Oliver is more aware of the sloth of his masters than the animals in Animal Farm, but he too is not fully conscious of the greed his masters are guilty of. Through Orwells use of narration it can be observed that he wished for the novel not to be read by a widespread readership but to be read by those whom he wished it to affect most: political people and those of intellectual nature. Animal Farm was Orwells method through which he interpreted the highly contentious issue of Bolshevism and explained it to others who wished to think about it.

Platos Ideal City Essays (1603 words) - Socratic Dialogues

Plato's Ideal City Plato's Ideal City Socrates' ideal city is described through Plato in his work The Republic, some questions pondered through the text could be; How is this an ideal city, and is justice in the city relative to that of the human soul? I believe Socrates found the true meaning of justice in the larger atmosphere of the city and applied that concept to the human soul. Socrates describes his idea of an ideal city as one that has all the necessary parts to function and to show that justice is truly the harmony between the three sections of the city and soul in the human body. Plato introduces the idea of the happiness between groups in Book IV. Plato says, in founding the city we are not looking to the exceptional happiness of any one group among us but, as far as possible, that of the city as a whole.(Plato 420b). I agree that in order to examine one thing that is difficult to comprehend, it is wise to look on a larger scale. In this case, Socrates had to examine the difference of a whole city and other concepts of cities in order to determine justice in the world and inner soul. In order to develop the perfect city Socrates had to develop the other ideas that contribute to the ideal city, the City of Need, and the City of Luxury in order to develop the Perfect City. I believe Socrates in-depth discovery process for the perfect city is a great philosophical look into the idea of justice. Socrates brought up a subject many men at that time would never have thought about and Plato believed that the idea of justice was worthy of writing a literary work to pass his political philosophy on to future generations. Since the crucial elements of justice may be easier to observe on the larger scale like a city than on one individual. The focus for Socrates is a perfect city, because the city will represent human soul, Socrates says; we'll go on to consider it in the individuals, considering the likeness of the bigger in the idea of the littler?(Plato 369a). Plato's ideal city is really the search for the truth of justice, if Socrates is able to find the relationship between the soul and city in his ideal city then he would have the true meaning of justice. We saw from the reading how he came about braking down the city's parts and also that of the soul in order to see the reaction between three different regions which Plato and Socrates describe in The Republic. According to Plato, Socrates broke down the perfect city into three parts; each part is tied to a specific virtue that he believes will help define justice. The three virtues are wisdom, courage, and moderation. Wisdom is the whole knowledge, which describes the rulers of the city. The rulers should be the ones who incorporate philosophy and ruling together to rule the city wisely. Courage describes the guardians, who's job was to defend the city from invasion and take new lands for the city. The third virtue of the ideal city was moderation which is the concept of self-control and knowing ones role, also the concept of one man, one job. The ideal city described in the work is ideal to me because it relates all essential parts to bring harmony among the different kind of people and the virtues that go hand in hand with to bring about justice. Therefore, the question arises, if I would want to live in the ideal city Plato has described in the work. My answer would be yes because it seems that everyone has a specific role to follow depending upon their abilities, both physically and mentally. When I look back to the early cities Plato discussed I agree with the city of need, but that is only part of the whole scheme of things. We need to add the luxurious things and leaders and the people to protect the city. No one of those first two cities could be great by its self, sure each one had their strong points but together they are harmonious to develop