Microbiology Paper Essay Example for Free

Microbiology Paper Essay Definition: Protists are organisms in the kingdom Protista. These organisms are eukaryotes, meaning they are made up of single or multiple cells which all contain a nucleus enclosed by a membrane. The protists are a diverse group of eukaryotes that cannot be classified as animals, plants, or fungi. Organisms in the Protista kingdom include amoebae, red algae, dinoflagellates, diatoms, euglena and slime molds. Also Known As: Protista Examples: One type of protist in the marine environment is Irish moss, which is a species of red algae. Diversity of Protists Introduction Protists are Eukaryotes that are not fungi, plants, or animals. This polyphyletic group includes a wide variety of organisms. Most groups of protists are unicellular but some are multicellular. Molecular evidence suggests that protists include several different lineages and therefore is not a kingdom. Some lineages are more closely related to either Fungi, plants, or animals than they are to other protist groups. Plants,fungi,and animals evolved from protist ancestors. Protists are a very diverse group and include organisms that range in size from single cells to complex structures more than 100 meters long. They show a variety of reproductive and nutritional strategies. Some protists are photoautotrophs, others ingest food (heterotrophs) or they release digestive enzymes into the environment and absorb organic molecules (saprotrophs). Some protists are both autotrophs and heterotrophs (mixotrophs). Most protists are aquatic but they are also found in moist terrestrial environments. They are important components of plankton in many aquatic food chains. Some groups of photoautotrophic protists are referred to as algae (green algae, red algae, brown algae, golden algae). The word algae is not used as a taxonomic category. Plasmodial (Acellular) Slime Molds Acellular slime molds are diploid, multinucleate masses that creep along the substrate and phagocytize dead organic material and microorganisms. The mass is one large cell referred to as a plasmodium. Note- Do not confuse the use of the word plasmodium here with the genus Plasmodium discussed under Apicomplexans above. Slime molds play an ecological role similar to that of fungi. They are decomposers, feeding on dead organic material. They differ from fungi in that slime molds ingest their food. Below: Physarum polycephalum. Click to view an enlargement. When environmental conditions are unfavorable such as when sufficient food or moisture are unavailable, sporangia form, and spores are produced by meiosis. Spores are resistant to environmental extremes and germinate when environmental conditions become favorable. They germinate to produce haploid cells that are either biflagellate (two flagella) or amoeboid. These cells can act as gametes, fusing to produce a diploid zygote that matures into the plasmodium. Cellular Slime Molds Cellular slime molds exist as individual amoeboid cells that phagocytize bacteria and yeast. When food becomes scarce, the cells aggregate to produce a mass that resembles the plasmodium of a plasmodial slime mold. This mass of cells may continue to move about but eventually will settle down and cells within the mass will produce fruiting bodies (reproductive structures). The cells at the tips of the fruiting bodies become spores. The spores germinate when conditions become favorable. The amoeboid cells are haploid. In the sexual phase of the life cycle, two amoeboid cells fuse to form a zygote. New amoeboid cells are produced by meiosis. Gymnamoebas Gymnamoebas move by cytoplasmic extensions called pseudopodia. They feed by phagocytizing (engulfing) their prey. Click on the image below to view movement in Amoeba. Amoeba.mpg Gymnamoebas are found in soil, marine, and freshwater environments. Amoeba proteus (below) is found in freshwater. Nutrition in some different types of protists is variable. In flagellates, for example, filter feeding may sometimes occur where the flagella find the prey. Other protists can engulf bacteria and digest them internally, by extending their cell membrane around the food material to form a food vacuole. This is then taken into the cell via endocytosis (usually phagocytosis; sometimes pinocytosis). Some protists reproduce sexually (gametes), while others reproduce asexually (binary fission). Some species, for example Plasmodium falciparum, have extremely complex life cycles that involve multiple forms of the organism, some of which reproduce sexually and others asexually.[13] However, it is unclear how frequently sexual reproduction causes genetic exchange between different strains of Plasmodium in nature and most populations of parasitic protists may be clonal lines that rarely exchange genes with other members of their species.[14] Role as pathogens Some protists are significant pathogens of both animals and plants; for example Plasmodium falciparum, which causes malaria in humans, and Phytophthora infestans, which causes late blight in potatoes.[15] A more thorough understanding of protist biology may allow these diseases to be treated more efficiently. Researchers from the Agricultural Research Service are taking advantage of protists as pathogens in an effort to control red imported fire ant (Solenopsis invicta) populations in Argentina. With the help of spore-producing protists such as Kneallhazia solenopsae the red fire ant populations can be reduced by 53-100%.[16] Researchers have also found a way to infect phorid flies with the protist without harming the flies. This is important because the flies act as a vector to infect the red fire ant population with the pathogenic protist.

Oliver Cromwell a Hero not a Villain Essay -- Leaders Politics English

Was Oliver Cromwell a hero or a villain? I think Oliver Cromwell was a hero. He was good – hearted and ambitious, and he wanted England to be at it’s best with no corruption and unfair methods. He thought Charles was not doing the right thing, so he worked hard and got him executed. Oliver Cromwell was a Member of Parliament (MP) and was against king Charles and his ways, so he worked hard and got the king executed. After that, he got offered the post of king, but he refused it, but was Lord Protector of the country. After some time, he dismissed parliament (because he thought they were getting selfish and greedy), and ruled on his own until he died of an infection on the 3rd of September 1658. Lots of people thought of Cromwell as a hero because he got the king executed for his bad ways and got the country in a really good, wealthy position. He put things right. Cromwell was a hero.â€Å" We need a person of great honesty and courage to clear the country of evil men making their riches from our poor starving and miserable countrymen. In other words, Oliver Cromwell†. The poor man’s guardian, 1831. These people were trying to show that Oliver Cromwell was perfect for the country. It is a newspaper so it would most probably be quite reliable. But you can never say because it is the ‘Poor Man’s Guardian’, and only focuses on the poor people’s views (whom Cromwell helped a lot). It does not state the views of wealthy people (whom Cromwell did not help too much). Oliver was a hero. He was brave rather than cruel, he did what he needed to and acted in god’s name when he killed lots in Drogheda. He did not mean to kill innocent peop le. He killed fewer than many are assuming. â€Å"It’s not fair to say he was like Hitler or Mussolini, ... ...t town on a Sunday’ or ‘no mending a dress on a Sunday’ (basically, no work on Sundays). No one was allowed to enjoy themselves because of these harsh rules. He did not allow people to play, even a small game of football. He banned Christmas. Just because his puritan beliefs, why should everyone else suffer? Just because he believes in it, why should he force other people to? Shouldn’t they have their own freedom? Cromwell was a villain. He just wanted others to suffer. Many people hated Cromwell, but about the same number thought of him as god. People’s opinions and impression on him were different, but personally I think he was a hero. He put some discipline into the country (there is none now), he tried to train people to be good and brave, but unfortunately, many rebelled. They did not get his policy. Many did. Oliver Cromwell, overall, I think he was a hero.

Davis’ argument against slavery causing the civil war Essay

As president of the Confederate States of America, I maintain that slavery was not why the South seceded from the Union. We Southerners seceded because the federal government was becoming increasingly pro-Northern in its views and imposing on our sovereign rights. Slavery was legal, yet the government threatened this institution and paid increasingly less heed to our rights. Just as the United States broke free from a British crown that overstepped its authority, the Confederacy formed to protect itself against an intrusive government under Northern sway. In addition, I am aware that many of our soldiers were not slaveholders; indeed, Southerners did not take up arms in order to defend slavery. Men who loved their homes, valued their freedom, and feared a Northern invasion and imposition on their rights formed the Confederate Army. No Southern soldier took up arms to help a slaveholder; many shouldered arms to fend off invasion by a people whose views opposed ours and who tried to coerce us into compliance with their ideals (Wikipedia). We also seceded because we wished to maintain our prosperity, which is a sacred right of Americans. Our economic and social system is the source of our vast wealth, and the Constitution grants us the right to defend it. The federal government favored Northern industry and legislated against us, which would have reduced us to poverty and placed the South in deep economic crisis. Our soil was becoming depleted and our plantations too numerous to be confined to its existing territory, and the federal government insisted on restricting where we could maintain our system, instead of allowing the people to decide (McPherson 78-116). We were not rebels against the federal government, since there was no concrete law binding us to the Northern states. The United States began as merely an association of sovereign states and the Southern states were not obligated to remain. REFERENCES Anonymous. â€Å"American Civil War. † Wikipedia. 8 November 2005. . Causes of the Civil War. † The American Civil War. 8 November 2005. . McPherson, James. Battle Cry of Freedom. New York: Oxford University Press, 1988.

Slavery A Stand On Slavery - 1605 Words

David Dillon Professor Pamela Roseman U S History 2111 November 11, 2015 Take a Stand on Slavery – Abolitionists The movement to eliminate slavery in the United States during the antebellum years was difficult and did not go unchallenged as there were many people who were pro-slavery while others were anti-slavery. Before the Civil War there was debate over the issue of slavery. Slaves were considered property, and were property because they were black. Many people in the South were strong advocates of slavery, while people in the North were opposed to it. In the South, slavery was a social and powerful economic institution. During this period in the south Pro-Slavery activists did not empathize with the system and conditions the†¦show more content†¦Frederick Douglass was another abolitionist who also spoke out vigorously about slavery. He himself was an emancipated slave who fought for the abolishment of slavery. He fought to demonstrate that it was crude, unnatural, ungodly, immoral, and unjust. During a July 4th Celebration he made it known that he despised the treatment of the slaves. He explained that this hypocrisy was aimed at the black population and so in his speech on the Fourth of July celebration he proclaimed to the anti-slavery individuals that â€Å"This Fourth of July is yours not mine† and â€Å"You may rejoice, I must mourn†. Frederick Douglass quoted from the Declaration of Independence, â€Å"All men are created equal; and are endowed by their creator with certain unalienable rights; and that, among these are, life, liberty, and the pursuit of happiness†. He wondered if the rights that are stated in the Declaration of Independence, apply to everyone in America, because he believed they should. He asked the question what the Fourth of July was to an American slave, and responded, to the American slaves that one day, is full of hyprocrisy. He wondered how people could celebrate liberty and equality where there was slavery in America. In support of his idea of how sorrow slavery was Douglas used imagery. He stated, â€Å"I see clouds of dust raised on the highways of the South; I see the bleeding footsteps; I