Enzyme used to break cell wall Essay Example for Free

Enzyme used to break cell wall Essay Aim To investigate the affect of Pectinase on the amount of juice produced from a stewed apple. I will investigate and explore the factors, which affect the rate at which juice is coming out of the stewed apple. There are many factors, which determine the rate at which reactions take place. The factors include temperature, concentration, surface area or pressure (if the substance is a gas) and a catalyst. However in this particular experiment I have chosen to investigate the rate of reaction when the concentration is the variable involved. Scientific Theories The theory of collisions Substances are made up particles. The particles in a particular substance can be atoms, ions or molecules. If two or more reactants collide with sufficient energy then a chemical reaction takes place producing a product. The particles must collide together hard enough to break the chemical bonds, kinetic energy is needed for this to occur. The initial energy or minimum energy that particles of reactants must have for them to react must have for them to react when they collide. The rate of reaction depends on how many reacting particles have this minimum energy. Heat is sometimes needed to start a reaction, which is referred to the activation energy. In many reactions often the products have less energy than the reactants. The more collisions and the harder the collisions between particles in a given time will result in the reaction speeding up. Temperature Faster collisions are only obtained by increasing the temperature. When the temperature is increased all the particles move quicker and collide more often. This will therefore speed up the rate of reaction. Surface Area (size of particles) If reactants are solid which is Magnesium in this particular experiment then if they are broken into smaller pieces this will increase the solids surface area. This will mean that the solution surrounding it in this case Hydrochloric acid will have more region to react on therefore creating more collisions between particles. This also will speed up the reaction. Concentration (or pressure if a gas) When a solution is made more concentrated which in this reaction will be to add more hydrochloric acid, which will mean there are more reactants to react with the magnesium therefore collisions are more likely. In gases though, increasing the pressure will mean the particles are more squashed up together consequently colliding more. This will speed up the rate of reaction. Catalyst This will speed up the reaction as it gives the reactants a surface to stick to where they can collide. Reactions only happen when particles collide with sufficient energy. From this theory as I am investigating the concentration of Pectinase we can say that if we increase the volume of Pectinase the rate at which the reaction takes place will increase, as the number of collision are more likely. Lock and Key Hypothesis Enzymes are substances that act as catalysts, in other words they increase the rate of reactions. Most enzymes are large protein molecules, with three-dimensional shapes. The substance with which the enzyme combines is known as the substrate. The reaction takes place on the surface of the enzyme called the active site. Enzyme molecules are usually very much larger than their substrates. The precise shape of the active site is important because it is complimentary to the shape of the substrate molecule, which fits into the active site, which is known as the lock and key mechanism. In this particular experiment the active site of the enzyme has a specific shape for the Pectin, which only it can fit into. The substrate is the pectin and the enzyme is the pectinase. In this specific experiment, we can say that if we increase the volume of Pectinase (the enzyme) the rate at which the pectin interacts with the active site of the enzyme will increase, therefore the rate at which the juice comes out of the stewed apple will also increase. Enzyme Activity 0i C 45i C Enzymes are usually damaged by temperatures above about 45i c, and as the graph shows, their activity drops off sharply when the temperature gets too high. Preliminary Work. In class we have performed a similar experiment involving the rate at which juice comes out of a stewed apple. However this time there were only two stewed apples, one solution contained the enzyme pectinase and the other without it. From doing this experiment, I found that the solution with Pectinase clearly produced more juice at a faster rate, than the solution without Pectinase. This proves that enzymes will greatly increase the rate of formation of the product. From doing that experiment I learnt a lot of things, which I would have to change in my final experiment, for example a more accurate measuring cylinder. Prediction. I predict that if I double the concentration of Pectinase, the rate at which the juice comes out of the stewed apple will also double. And the reaction time will be cut in half. This is because as the volumes of Pectinase will increases therefore there will be more Pectin interacting with the active site of Pectinase, therefore more cell walls will be breaking and more juice will be produced. Also, because of the simple concept that before particles can react they must collide, therefore there will be more particles in a smaller volume therefore collision between particles will be more likely and consequently the reaction will speed up. I can also predict that if I half the concentration of Pectinase, this will also half the rate at which the reaction takes place and the time taken for the reaction to take place will double. This is because the decreased number of particles also means that the chance of collision will also reduce. Therefore the time taken for the cell wall in the apple to break will decrease and result in less juice being produced over a certain period of time. I also predict that the amount 0of juice produced will be proportional to the time. Apparatus Pectinase (enzyme used to break cell wall) 4 100cmi beakers 10cmi measuring cylinder Stewed Apples (chopped up) Filer paper Water Stop- clock (to record the amount of juice being produced) Scale (used to measure the mass of the steed apples) Funnel Syringe Variables The variable, which will be changed in this experiment to alter the rate of reaction, is concentration. At least five readings are needed in order to draw a graph and to have significant amount of results, to prove he prediction. The concentration of Pectinase will change, as water will be added to dilute it. The total volume of Pectinase and water in each experiment will always be 5cmi making it a fair test. The table below shows the different concentrations used in the experiment Concentration of Pectinase Concentration of Water 5cmi 0cmi 4cmi 1cmi 3cmi 2cmi 2cmi 3cmi 1cmi 4cmi 0cmi 5cmi Plan The apparatus will firstly be collected and set up. The stewed apple will be weighed in a 100cmi beaker. The volume of Pectinase and water will be taken out of the container using a syringe. The Pectinase and water will be measured using a measuring cylinder (10cmi)

Comparing Black Elk Speaks and The Lone Ranger and Tonto Fist Fight in

Comparing Black Elk Speaks and The Lone Ranger and Tonto FistFight in Heaven      Ã‚  Ã‚  Ã‚   Traditionally, Native American Literature has been an oral genre. Although Native American Literature was the first American literature created, it has been the last to be recognized -and, to some extent, is still waiting for full recognition (www.usc.edu). With the Indian being forced to assimilate, their literature was forced to take on a written form. Although the traditional way of storytelling has changed, Native American Literature has survived. In it's written form, it is being shared with a larger population. Black Elk Speaks (Neihardt 1932) and The Lone Ranger and Tonto FistFight in Heaven (Alexie 1993) are two Native American works of literature that have gained recognition. Although they are similar in that they tell the Native American experience, they are also different in that they tell the experience from different times in history.    Both books tell the story of the Native American's day-to-day struggles. Black Elk Speaks tells of the Indians struggles during the middle '80s of the 19th century. The Lone Ranger and Tonto Fistfight in Heaven tells the modern day struggles of the Indian. Although the books are written at different times in history, they still tell of the prejudice, disease, poverty and day-to-day struggle the Native American faces in the attempt to live in two worlds. In Black Elk Speaks the Indians were fighting to survive and keep their land. The white man (Wasichus) took away the Indian's land, brought in diseases, and killed their men, women and children. Although the Indians during this period in history suffered a great loss, they did manage to survive.    Sherman Alexie tells of the Indian... ...ght in Heaven. New York: HarperCollins, 1993. Kirkus Reviews. "Amazon.com: Editorial Reviews: The Lone Ranger and Tonto Fistfight in Heaven." 1 July 1993. < obidos exec www.amazon.com> Ts/book-reviews>. "Native American Literature." 10 October 2000. < isd www.usc.edu> archives/ethnicstudies/Indian_lit.html>. Neihardt, John G. Black Elk Speaks: Being the Life Story of a Holy Man of the Ogalala Sioux. New York: William Morrow, 1932. Walker, Jr., Theodore. "Vine Deloria, Jr. on the authenticity of Black Elk Speaks." 24 March 1997 <http://www.smu.edu/~twalker/blkelk0.htm>. 10/23/00. Whitson, Kathy J. Native American Literatures: An Encyclopedia of Works, Characters, Authors, and Themes. Santa Barbara: ABC-CLIO, Inc, 1999. Young Adults Books. Rev. of The Lone Ranger and Tonto Fistfight in Heaven. 11 March 1996. .       Comparing Black Elk Speaks and The Lone Ranger and Tonto Fist Fight in Comparing Black Elk Speaks and The Lone Ranger and Tonto FistFight in Heaven      Ã‚  Ã‚  Ã‚   Traditionally, Native American Literature has been an oral genre. Although Native American Literature was the first American literature created, it has been the last to be recognized -and, to some extent, is still waiting for full recognition (www.usc.edu). With the Indian being forced to assimilate, their literature was forced to take on a written form. Although the traditional way of storytelling has changed, Native American Literature has survived. In it's written form, it is being shared with a larger population. Black Elk Speaks (Neihardt 1932) and The Lone Ranger and Tonto FistFight in Heaven (Alexie 1993) are two Native American works of literature that have gained recognition. Although they are similar in that they tell the Native American experience, they are also different in that they tell the experience from different times in history.    Both books tell the story of the Native American's day-to-day struggles. Black Elk Speaks tells of the Indians struggles during the middle '80s of the 19th century. The Lone Ranger and Tonto Fistfight in Heaven tells the modern day struggles of the Indian. Although the books are written at different times in history, they still tell of the prejudice, disease, poverty and day-to-day struggle the Native American faces in the attempt to live in two worlds. In Black Elk Speaks the Indians were fighting to survive and keep their land. The white man (Wasichus) took away the Indian's land, brought in diseases, and killed their men, women and children. Although the Indians during this period in history suffered a great loss, they did manage to survive.    Sherman Alexie tells of the Indian... ...ght in Heaven. New York: HarperCollins, 1993. Kirkus Reviews. "Amazon.com: Editorial Reviews: The Lone Ranger and Tonto Fistfight in Heaven." 1 July 1993. < obidos exec www.amazon.com> Ts/book-reviews>. "Native American Literature." 10 October 2000. < isd www.usc.edu> archives/ethnicstudies/Indian_lit.html>. Neihardt, John G. Black Elk Speaks: Being the Life Story of a Holy Man of the Ogalala Sioux. New York: William Morrow, 1932. Walker, Jr., Theodore. "Vine Deloria, Jr. on the authenticity of Black Elk Speaks." 24 March 1997 <http://www.smu.edu/~twalker/blkelk0.htm>. 10/23/00. Whitson, Kathy J. Native American Literatures: An Encyclopedia of Works, Characters, Authors, and Themes. Santa Barbara: ABC-CLIO, Inc, 1999. Young Adults Books. Rev. of The Lone Ranger and Tonto Fistfight in Heaven. 11 March 1996. .      

Computer Network Assignment

COMPUTER NETWORKS 4TH MARCH 2012 Examination Paper Answer ALL questions. Clearly cross out surplus answers. Time: 2 hours Any reference material brought into the examination room must be handed to the invigilator before the start of the examination. ANSWER ALL QUESTIONS Marks QUESTION 1 a) State FOUR (4) principles underpinning the Open Systems Interconnection (OSI) Reference Model. b) Describe the purpose of the physical layer of the OSI Reference Model. c) State THREE (3) elements of network design that relate to the physical layer of the OSI Reference Model. ) Describe the purpose of the data link layer. 4 1 3 2 Total 10 Marks QUESTION 2 a) b) c) d) Define the term a packet as used in computer networks. Briefly describe the THREE (3) key components of a packet. Explain the difference between a LAN, MAN and WAN. Describe how signal reflection could be a problem in an Ethernet LAN and explain how this is prevented. 1 3 3 3 Total 10 Marks QUESTION 3 a) b) c) d) Explain why wireless t echnology was not initially widely adopted. State THREE (3) advantages to using wireless peripheral devices. Describe what a wireless adapter is.Windows 7 Check Your UnderstandingDescribe what an access point is. 3 3 2 2 Total 10 Marks QUESTION 4 a) b) c) d) Explain what physical topology is. Explain what logical topology is. Describe how physical topology and logical topology relate to each other. Describe how point to point networks operate. 2 2 2 4 Total 10 Marks QUESTION 5 a) b) c) J State FIVE (5) factors to consider when choosing physical media for a computer network. State FOUR (4) advantages to using fibre-optic cable as a network medium. State the main disadvantage to using fibre-optic cable as a network medium. 4 1 Total 10 Marks QUESTIONS CONTINUE ON NEXT PAGE Page 2 of 3 Computer Networks March 2012 Formatted/HW Â © NCC Education Ltd 2012 Marks QUESTION 6 a) b) Explain what a repeater is and briefly describe how it works. Explain what a router is and briefly describe ho w it works. 6 4 Total 10 Marks QUESTION 7 a) b) c) List FIVE (5) key factors to take into account when locating wireless access points. You have located an access point in the best available place for your wireless network but it is not providing the complete coverage you require.State THREE (3) options you have to extend the coverage of the wireless network. Your wireless network allows public access via a login page. Describe TWO (2) features that should be included in your login page. 5 3 2 Total 10 Marks QUESTION 8 a) b) c) d) A secure network offers privacy. Explain what privacy is in this context. A secure network offers integrity. Explain what integrity is in this context. A secure network offers availability. Explain what availability is in this context. Describe a man-in-the-middle attack. 2 3 2 3 Total 10 Marks QUESTION 9 a)Firewall traffic blocking rules can be created for network traffic based upon a number of different properties. State THREE (3) properties that are use d to create firewall rules. b) Explain what a router firewall does. c) List FOUR (4) key tasks that are vital for managing a firewall. 3 3 4 Total 10 Marks QUESTION 10 a) b) c) State the THREE (3) main functions of a Network Operating System (NOS). Describe how a redirector works. State THREE (3) network services that a NOS will typically enable. 3 4 3 Total 10 Marks END OF EXAM Page 3 of 3 Computer Networks March 2012 Formatted/HW Â © NCC Education Ltd 2012

William Cuthbert Faulkner s Life - 1128 Words

William Cuthbert Faulkner is more than a famous Mississippi writer. He is a renowned figure, not only for Southern writers, but for writers throughout the world. Faulkner drew the scenes and characters for his novels and short stories from observations made during his childhood and adult life in his hometown, Oxford, Mississippi. During what is generally considered his period of greatest artistic achievement, a span of forty years, from 1929 to 1942, Faulkner accomplished more than most writers accomplish in a lifetime of writing (Minter 2). Because of his dedication to his writing and the acceptance of his ideas by readers from around the world, Faulkner was awarded the 1949 Nobel Prize for Literature. Faulkner is a writer who utilizes†¦show more content†¦In July 1918, compelled by despair at a broken love affair, Faulkner joined the British Royal Air Force (RAF) as a cadet pilot under training in Canada. After returning home, he enrolled for a few university courses, publ ished poems and drawings in campus newspapers. After working in a New York bookstore for three months in the fall of 1921, he returned to Oxford and ran the university post office there. In 1924 Phil Stone’s financial assistance enabled him to publish his first piece, The Marble Faun. There were also early short stories, but Faulkner’s first sustained attempt to write fiction occurred during a six-month visit to New Orleans. One of the most unique creations to come from Faulkner’s writings is the region of Yoknapatawpha County, an imaginary area in Mississippi with an intriguing history and a diverse population. Transforming his â€Å"postage stamp of native soil† into a fictional setting allowed Faulkner to explore, articulate and challenge â€Å"the old verities and truths of the heart† (Millgate, â€Å"William Faulkner† 1). Faulkner, being a product of the Deep South, held onto his southern values and wanted to challenge his readers to not only understand his setting but wishes for them to explore it. Yoknapatawpha County is a condensed version of the South as a whole, and Faulkner’s novels examine the effects of traditional values and authority on allShow MoreRelated Writers of the 1920s Essay485 Words   |  2 Pagesthe 1920s The 1920s had many influential writers in literature. While reaching this time period it is almost certain that the names William Faulkner, Earnest Hemingway, and F. Scott Fitzgerald will be found. Each of the writers has their own personal style of writing and each one of the lives has influenced what they write about to even the way they each portray their literature. William Cuthbert Faulkner was born into a financially stable family from New Albany, Mississippi. 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Faulkner won two Pulitzer Prizes for Fiction and the Nobel Prize in Literature. â€Å"A Rose for Emily† is a short fascinating story written by William Faulkner and it was his first short story published in a national magazine. The story involved an old womanRead Moreâ€Å"a Rose for Emily, † â€Å"Young Goodman Brown† and â€Å"Good Country People, †1823 Words   |  8 PagesIsolation: Loneliness from Society The time moves on for all people. If we cannot come to terms with that, bad things can happen. A short story, A Rose for Emil, by William Faulkner, was first published on April 30, 1930. William Cuthbert Faulkner was born in New Albany, Mississippi, on September 25, 1897. He is one of the greatest writers in America and obtained Nobel Prize laureate. As he grew up in New Albany, Mississippi, the Southern society influenced to him. Through his works such aRead MoreA Rose For Emily, By William Faulkner Essay2322 Words   |  10 Pageswhereas solitude is the state of being alone. 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His economy of words, intensive brooding, and blooming imagination made his characters