The Long Walk Home Essay free essay sample

There was a lot of striking moments in this movie. But to me the most striking and memorable moment was the last scene in the movie. This was the most memorable moment because the way the black people were getting yelled at just because the wanted to be as equal as everyone else. Also I liked how they didn’t retaliate and all they did was sing. They really proved violence didn’t solve anything. Miriam Thompson moral development at the beginning of the movie and the end of the movie are almost completely different at the beginning of the movie she was not as racist as the rest of the white people in the movie. She thought of Odessa as her wife and that’s all at the beginning of the movie. In the middle she started to fell for Odessa because of the boycotts and drove her to and from work. We will write a custom essay sample on The Long Walk Home Essay or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Later she began to help the boycott by joining the carpool. At the ended she was a completely different person and her morals changed. ) Odessa Cotter moral development didn’t really change during the story. I say this because she was always respectful and didn’t really hate the white people. She didn’t hate them because she knew it was morally wrong. 4) a) I think that the â€Å"N† word should have been used in the movie. I only think this because the movie wouldn’t sound so realistic. Also that’s the term people really used back then so there’s no point in trying to hide it b) The â€Å"N† word is used a lot today. It kind of feels like an insult when other people than black people say it. This is only because the way it was used back then 5) This film really showed how segregation was a leading cause of poverty by many black people. In this movie the black and white people lived in completely different places. Black people house were all small in a little rundown. Also the neighborhoods weren’t as nice. On the other hand most white people had luxurious houses. The towns were never dirtied up and clean. Also white people tended to have better paying drops because of segregation. That also meant they had more money.

US Media representation of Saudi Arabia

US Media representation of Saudi Arabia Introduction The mainstream elite media such as Newsweek, The New York Times, CNN, CBS, NBC, Washington Post, Fox, and ABC are perceived by Arab world people as biased in addressing issues of foreign affairs with regard to the Islamic world.Advertising We will write a custom essay sample on US Media representation of Saudi Arabia specifically for you for only $16.05 $11/page Learn More Saudi Arabia is one of the Islamic countries that have always been scrutinized by the mainstream media in the United States. Many citizens of Saudi Arabia blame the US media for the American stereotypical representation of Arabs. This essay explores some of the recent US media representation about Saudi Arabia, and provides an insight into the effects of this aspect. The US Media representation of Saudi Arabia In the last two years, the mainstream US media has portrayed Saudi Arabia as a country that does not value rights and freedoms of women (Subramanian 1). They majorly poi nt out the Muslim laws and the Arab culture has the impediment of women empowerment and rights. With reference to CNN, the arbitrary rules found in the Arab world restrict womens freedom of putting on what they want (Ghitis par. 3). They are also denied the right to drive cars. This report was carried exclusively by CNN and ABC news in October and November 2013. The New York Times refers to Saudi Arabia as the only country in the world that does not allow its women to drive (Hubbard par. 5). This media reflection of the womens rights in Saudi Arabia is positive, especially to our women who have been treated unjustly by culture and religion (Ghitis par. 4). This is positive reporting from the US media. However, on a negative note, the media are representing Saudi Arabia as a nation that does not respect womens rights. Politics and democracy is another important issue that the United States has highlighted about Saudi Arabia. The New York Times depicts Saudi Arabia as a monarchy coven ant and as an impediment to democracy. Khashoggi (2012) points out that the monarchical system of government denies the population the rate to vote and elect their leaders (Khashoggi par. 2). In regional politics, Saudi Arabia is reflected as a nation that prefers to work behind the scenes with a selfish agenda of promoting their vision. In his article, Tom Philips (CNN) argues that Saudi has always been at the forefront in pushing for Gulf regional stability (Phillips par. 3). This is a positive observation of the American media. However, due to its domestic, political, and democratic systems, the reason behind its push for regional integration is to take top slots.Advertising Looking for essay on communications media? Let's see if we can help you! Get your first paper with 15% OFF Learn More The United States media portray Saudi as a good business destination in the Middle East. It acknowledges that the country is the world’s most developing and the growing economy (â€Å"Business culture in the kingdom of Saudi Arabia par. 3). The CNN report owes this to excellent business culture, business code and management style. This is a big compliment by the United States media on Saudi Arabia. The US media has been behind the stereotypical representation of Saudi and the entire Arabs (Phillips par. 5). This has always been negatively perceived though not very true. This has led to the Arabs being depicted as people who care less about human rights, undemocratic, and always under the confines of religion (Hubbard par. 3). This indeed has resulted in negative attitudes of the American people towards Saudi Arabia and its citizens. Conclusion Media plays a major role in developing stereotypes. This is evident in the manner in which the American mainstream media have represented Saudi Arabia. The US media has demonized Saudi Arabia in matters ranging including culture, human rights, and politics. However, in economic terms, Saudi Arabia h as been well represented by the American media. Business culture in the kingdom of Saudi Arabia. CNN, May 27, 2013. Web. Ghitis, Frida. Dont tell Muslim women what to wear. CNN, November 3 2013. Web. Hubbard, Ben. Saudi women rise up, quietly, and slide into the drivers seat. New York Times, 27 Oct. 2013: 6. Khashoggi, Jamal. The Saudi King Never Promised Democracy. New York Times, August 29, 2012. New York Times, Web.Advertising We will write a custom essay sample on US Media representation of Saudi Arabia specifically for you for only $16.05 $11/page Learn More Phillips, Tom. Whats got into the Saudis?. CNN, October 19, 2013. Web. Subramanian, Courtney. Saudi women fined In protest on driving ban. Time.Com (2013): 1.

Motivational Theories Essay Example | Topics and Well Written Essays - 1250 words

Motivational Theories - Essay Example The X and Y theory The theory X and theory Y formulated by Douglas Mc Gregor in the year 1960 positions previous negative perceptions about employees (Theory X) against a positive outlook towards employees and mindset of individuals (Theory Y) eg: Theory X- People inherently dislike work. Theory Y - People view work as being as natural as play and rest. Motivator- Hygiene factors theory : The hygiene factors theory by Frederick Herzberg in the year 1966 is another path breaking concept which clearly listed the factors of job satisfaction and dissatisfaction. Most accurately explained as Motivator factors that increase job satisfaction and Hygiene factors whose absence can create job dissatisfaction. The essence of the theory is that hygiene factors are the essentials of any employee or an individual at work they are - Security, Salary, Supervision, Company policy, Working conditions and Peer relationship. On the other hand, motivator factors are - work itself, Responsibility, recognition, achievement, advancement and growth. However, the first two theories give a general insight about an individual's needs and perceptions to understand a human's psychology about work was the theory of Frederick Herzberg that clearly lists the requisites of any given job for an individual. The three needs theory -... The highlight of the theory is direct relation it draws to the relevance to the word "Motivation' or factors that motivate. In this case factors that motivate individuals to perform and succeed. The needs theory includes all factors that come from within an individual. Eg: Competitiveness, influence that one exerts on another, need for achievement, acceptance and friendship. Goal Setting theory and Equity theory: The goal setting theory by the Stacey Adams in the year 1965 states that specific goals set by any organization for an individual increases performance in the of sales the goal is monthly target of sale on products to be achieved. The theory further goes on to explain that acceptance of a difficult goal only results in higher performance, even when compared to a goal that is easily achievable. The equity theory is nothing but the simple equation that any individual draws between the efforts and rewards an individual is constantly trying to match both sides by reducing efforts or increasing the same depending on the rewards and recognition expected. Eg: If a sales representative sees the reward or recognition is receives after he meets the required monthly target is unequal to his effort or sincerity he is bound to under perform the following month. Expectancy Theory: This theory by Victor Vroom in the year 1964 aims to substantiate the motivation theory more accurately for any sales unit. Victor Vroom explains the theory in three simple questions: 1. How hard will I have to work - Effort 2. What is the reward - Reward 3. How attractive is the reward - Attractiveness of reward. Thus the above mentioned theories in one way of or the other help in understanding the various factors of

The Scientific Method Essay Example | Topics and Well Written Essays - 750 words

The Scientific Method - Essay Example To determine whether the hypothesis is correct, an experiment is designed. Any external factors that can affect the results should be minimized. This means, set-ups that do not contain the test variable (negative control) should be included so that the design is ensured to be not presenting any effectors other than the variable being tested. As well, a positive control is included so that it is ensured that the experimental method is capable of producing the result being tested (Carter, 2010). For this experiment, six set-ups will be made, with three replicates each. Replicates are important so that the outcomes cannot be attributed to chance. The more replicates having the same outcomes, the more established that data is. Experiments will begin when the sun rises, possibly around six in the morning. Thus, set-up will start minutes or hours before that Experimental Set-up For the first set-up, three 1 ft. Coleus plants will be placed outside, in the area where it can be maximally exposed to the sun. They will be placed beside one another. On the other hand, another three will be placed in a very dark room/closet that will only be opened after the experiment. For the third set-up, the upper half of the shoots, stems and leaves included, will be covered by aluminium foil, and for the fourth set-up, it is the lower half that will be covered. These six will be exposed to the sun together with the 1st set-up. For the fourth and fifth set-up, a lamp will be placed beside the left and the right side of plants, respectively. Experiment proper The plants will remain on their respective places from six in the morning to twelve in the afternoon. Hourly, specifically at 6 a.m. (start), 7 a.m., 8 a.m., 9 a.m., 10 a.m., 11 a.m., and 12 noon, pictures of the plants will be taken to observe and record any macroscopic changes in the growth of the plants. Then, the sho ots will be divided into four, first into top and bottom halves, and then to left and right. The same

Importance of The Web-based Software for Students Assignment

Importance of The Web-based Software for Students - Assignment Example Campus cruiser software has a fully and seamlessly integrated LMS that students can access from their portal (TimeCruiser, 2007). The seamless integration of course cruiser and LMS enable students to access the campus LMS through their student’s portal and within a single sign-in. To facilitate user its friendliness, the software is designed using familiar tools that facilitate student’s learning experience and use of the system. The system also enhances streamlined and wide range course management and collaboration between the students and the school’s management. The campus cruiser also provides essential academic tools that are required for the management of instructions. Some the basic tools include gradebook, assignments, course level charts, file sharing tools and research tools. The grade book enables students to set up instructions concerning the grades that they would wish to achieve. Gradebook might include assignment tools that enable students to manage their assignment and share research questions. The course-level forums & chart enables a student to share experiences and information relating to their coursework and assignments (TimeCruiser, 2007). On the other hand, the file-sharing tools enable students to share content with other students taking a particular course. Finally, the online journal tool facilitates student’s online research and provides essential information concerning academic honesty. The course cruiser has considerable benefits to an institution. These benefits can be an analyzed by considering the benefit achieved by each of the stakeholders. For instance, the faculty benefits from an increased interaction among students and course instructors. This facilitates exchange of ideas and other related academic materials. The system also enhances streamlined and wide range course management and collaboration between the students and the school’s management.The campus cruiser also provides essential academic tools that are required for the management of instructions.  

Nuclei And Mitochondrial Fraction

Nuclei And Mitochondrial Fraction The objective of this experiment is to prepare a nuclei and mitochondrial fraction using differential centrifugation, from a rat liver homogenate sample. The amount of activity of mitochondria in the fractions can be measured using succinate dehydrogenase (SDH) as a marker. To measure the percentage recovery of the SDH of Mitochondrial, Nuclei and supernatant fractions in comparison to the Homogenate and to Calculate the specific and relative activity of SDH in each fraction. Figure 1: Shows a typical animal cell with the individual organelle components. Figure 2: Shows the typical features and functions of the organelles of interest in this report. Figure 1 + 2 Created on Microsoft paint with reference to Essential Biology (2004) Individual organelles differ in size but are all usually around 10nm in diameter. There is a small surface area and size/density depends on the organelle, the smaller organelles being lysosomes and ribosomes. Mitochondria differs in cell type depending on the energy demand of that organ, the more ATP that is required in a particular organ the more mitochondria found. E.g. more mitochondria found in heart and liver cells than in a white blood cell like a lymphocyte. Smaller organelles include lysosomes and ribosomes. Metabolism can be detected using various methods such as use of inhibitors. These can be both competitive and non-competitive, an example is seen with arsenic with inhibits pyruvate dehydrogenase. Another method is with the use of radioisotopes to measure activity aswell as histochemistry, immunocytochemistry and electromicroscopy. Preparation of the homogenate occurs in various stages. Firstly the homogenisation of liver cells. This can be done using a Potter Elvehjem homogeniser to extract organelles without damaging the actual cell. This is a simple and effective homogenisation method. A small gap is made within the cell wall which is then pressurised which forces the contents i.e organelles, cytoplasm etc. out of the cell. This occurs at a low temperature and mild pH, and to keep the isotonic solution a sucrose buffer is used, therefore since there is the same water potential inside the cell and outside the cell there is no net movement of water (osmosis) and thus the cell remains the same size. Homogenized cells also must be kept at low temperatures to prevent autolysis (the degradation of a cell by its enzymes). (www.bookrags.com). Figure 3 shows a classic Potter Elvehjem homogeniser Image taken from (umwcellbiology.org) The second stage is fractionation of the homogenate sample. This process is called centrifugation and can be further split into either a differential centrifugation or a density gradient centrifugation. The differential centrifugation splits the impure fraction into separate compartments due to the size of the various organelles in question and there density. The centrifuge applies a gravitational force onto the sample to separate components. The rate of centrifugation is determined by the acceleration or speed applied to the homogenate and is usually measured in revolutions per minute (RPM) or g. Depending on the density of the organelles will determine their isolation at a given speed. The higher density organelles and the bigger organelles separate at a lower speed centrifugation. (K. Wilson 2005). The separation forms a pellet which is the precipitate proportion of the sample and the component of interest and a supernatant which is the liquid component. The supernatant readily de canted from the sample without removing the precipitate. Diferemces in centrifugation occur due to the techniques used, differential centrifugation is based upon the sedimentation rate of particles and thus the sedimentation rate separates them based on size and density. After initial sedimentation the largest particles separate first into pellet and supernatant (K. Wilson 2005). Density gradient centrifugation separates organelles using a media. Various media can be applied and depending on the particles will be best for certain types and may not work well for others. (K. Wilson 2005). The 4 fractions we will obtain are nuclei, mitochondrial, supernatant and homogenate. Various tests can be carried out to distinguish between fractions and to determine their actual purity, testing for specific enzymes can code for the activity occurring in the cell fractions therefore indicating the most abundant component. Some tests include: Testing for DNA in both nuclei and mitochondrial fractions. This is because DNA is contained within the nucleus but also within the mitochondria. This is because relating to the endosymbiotic theory mitochondria was a separate aerobically respiring bacterial cell which was later engulfed by an early eukaryotic cell to merge into one aerobically respiring cell. Mitochondria is maternally inherited in the case of the majority of multicellular organisms, this is due to the higher number of mtDNA molecules in the ooecyte and much fewer in a sperm cell which are mostly degraded before fertilization takes place. Test for histones which indicate nuclei fraction as well as testing for various enzymes such as ATPase found in cytoplasmic (supernatant) and mitochondrial fractions and phosphotase kinase indicating microsomes and golgi apparatus are present. Some enzymes are exclusive to the citric acid cycle which occurs in the mitochondria, therefore testing for these enzymes indicates the presence of mitochondria in a fraction. The enzyme marker to test for mitochondria which we use is succinate dehydrogenase which is exclusive to the inner mitochondrial membrane. Succinate dehydrogenase is formed only during the citric acid cycle so is only given as an indication of mitochondria. However, since during the homogenisation process the mitochondria could potentially burst spilling their contents into the cytoplasm (supernatant fraction), this does not therefore give an accurate indication of mitochondria present in a fraction. Succinate dehydrogenase breaks down succinate into fumurate, therefore t he measurement of formazan indicates presence of succinate dehydrogenase. Measuring Succinate Dehydrogenase Activity (Red Formazan assay) This occurs in 2 reactions: 1: succinate + FAD à ¨ fumarate + FADH2 SDH breaks down succinate into fumarate. This is an oxidation reaction since the succinate loses 2 electrons, in addition a reduction of the enzyme flavin adenine dinucleotide occurs (FAD gains 2 electrons) (FAD + 2 electrons à ¨ FADH2) Figure 4: Shows the redox reaction which occurs with succinate and FAD. Image taken from natuurlijkerwijs.com SDH activity is measured by the formation of formazan a deep red compound formed from the reduction on a tetrazolium salt. The reduced FADH2 reduces tetrazolium salt (INT). 2: FADH2 + INT à ¨ FAD + formazan Centrifugation and calculating the relative centrifugal field. (K. Wilson 2005) G = W2r = 4 II2 r (rPM)2 = 1.1110-5r (rPM)2 3600 G= Relative centrifugal force (RFC) r = Radical distance from axis of rotation w = Angular velocity rPM = Revolutions per minute. T = 9 É ² (In Rt/Rb) 2 W2rp2 (Pp -P) É ² = Viscosity of medium rp = Radius of particle Pp = Density of particle P = Density of medium Rt = Radius to top of centrifuge tube Rb = Radius to bottom of centrifuge tube. There are many differences in types of centrifuges available and results depend on the speed of the centrifugation and whether a vacuum is present and the type of rotor used. (K. Wilson 2005) Analysis of marker enzymes in subfractions determines the recovery of subcellular organelles, with comparison to previous tests, quantative data can be used to assess contamination of fractions. Showing whether the subfractionation method has been successful or not. These tests also hold health benefits and implications e.g. microsome C causes cell death and can be found in mitochondrial fractions, however in cancer patients no microsome c is present, indicating no cell death will occur a common feature of cancer cells. Enzyme measurement in subcellular fractions however does hold some implications such as the solubility of the environment which may cause differences in enzyme function. Another implication is latency of enzymes, this refers to whether proteins are bound to the enzyme which in turn activates them once bound signalling enzyme function. There may also be low recovery of enzymes in the fractions due to poor recovery of the organelles which they come from, in particular if the enzyme is confined only to a specific region. Over the 3 week period centrifugation will separate the fractions according to size/density and separating the sample into the pellet and supernatant fractions. The speed of the centrifuge determines whether the pellets will separate. A lower speed is needed to separate the nuclei fraction due to the higher density, whereas the higher speed is needed to separate the supernatant due to the smaller density remaining organelles. (K. Wilson 2005). The protein content is also measure for each fraction using the biuret assay, absorbance values are given which determine the protein content of each fraction. Finally succinate dehydrogenase is measured. This causes a redox reaction and causes e- ions are released, using formazan as an indicator this changes the colour of solution red, showing a redox reaction has taken place. From this research I can predict that the mitochondrial fraction is expected to have the highest results in specific activity due to fewer proteins present in that fraction. Results: Calculations: Formazans molar extinction coefficient (E490nm) = 20,100 M-1 cm-1 The specific activity and relative activity of the fractions can be determined by measuring the concentration using Beer- Lamberts Law: (www.chemguide.co.uk) A = ÃŽ µ x l x C A = Absorbance (no units) ÃŽ µ = Epsilon. The adsorbtion coefficient M -1 cm -1 l= Cuvettes light path length, this is the length of solution a light passes through (always 1 cm) C= Concentration of substance in M (moles in 1 litre) Rearrange to give concentration: C = A / ÃŽ µ x l Units: M-1 x cm-1 = 1 / M x cm C = A / ÃŽ µ x l Gives units: ( 1/ (1/M x cm) x cm). This can be simplified to give 1/ (1/M) And further simplified to give units: M (moles per litre or dcm -3) Know values: ÃŽ µ = the formazan adsorption coefficient is 20,100 M -1 cm -1 A = refers to the absorbance at 490nm values for each fraction are found in the mean-control table section. Using the equation: C = A / ÃŽ µ x l We can work out the concentration of formazan formed in the reaction. The concentration value is for 1 litre, therefore we must calculate the actual concentration from the actual assay volume used. Concentration = amount/volume rearranged to give A = C x V The final assay volume from week 3 is 6 ml* due to the addition of ethyl acetate. * Note by mistake 6ml of ethyl acetate was added instead of 4 ml giving a different final volume to the other groups. Converting 6ml into its litre value and x by the concentration gives the accurate mole product of formazan produced. Reaction time needs to be included to give the accurate units. Activity units can be determined using the following equation. Activity = Moles of formazan/reaction time (12 minutes) This gives the activity in M -1 Calculating total activity and specific activity of the fractions. Table 1: Total volumes from each cellular fraction. Fraction Total Volume (ml) Homogenate 12 Nuclei Fraction 12 Mitochondrial Fraction 12 Supernatant Fraction 26 To do this we need to take into the account: The total volume The total protein of the fraction. Dilution factor The total volume values for each fraction can be found in table 1. The sample of each fraction used was 0.2ml, therefore the amount of moles of formazan calculated is in 0.2ml. (0.2 / total volume) x moles of formazan in 0.2ml X by the dilution factor of each fraction to give the total activity for each fraction, the values are given in table 4. To determine the specific activity we must consider the total protein of the fraction. Values are given in table 3. Specific activity = Total activity of fraction/ total protein of fraction Table 2: Bovine serum albumin (BSA) solution concentrations Volume (ml) BSA (10mg/ml BSA 0 0.2 0.4 0.6 0.8 1.2 1.6 0.1m NaOH 2.0 (blank) 1.8. 1.6 1.4 1.2 0.8 0.4 Table 3: Values for BSA standard curve. See Graph 1 for the results from the corresponding fraction absorbance. Protein Amount (mg) 0 (blank) 2 4 6 8 12 16 Absorbance at 550nm 0 0.105 0.184 0.275 0.354 0.511 0.531 Table 4: Protein amount in homogenate and subcellular fractions. Homogenate 0.05ml Nuclei 0.2ml Mitochondria 0.2ml Supernatant 0.2ml Average Absorbance (550nm) 0.169 0.054 0.174 0.199 Protein amount in samples aliquot (mg) 3.6 1.18 3.8 4.15 Protein concentration in fraction (mg/ml) 72 5.9 19 20.75 Protein amount in fractions total volume (mg) 864 70.8 228 539.5 Graph 2: Shows the difference in protein amount amongst cellular fractions. Table 5: Actual concentration of fraction after dilution. Dilution Factor Actual concentration (mg/ml) Homogenate 20 3.6 Nuclei 3 2 Mitochondrial 20 0.95 Supernatant 1 20.75 Table 6: Formazan content absorbance at 490nm. Fraction Control Test 1 Test 2 Mean-Control Homogenate 0.132 0.58 0.52 0.42 Nuclei 0.21 0.352 0.326 0.13 Mitochondrial 0.057 0.391 0.265 0.27 Supernatant 0.132 0.52 0.33 0.29 Results for Homogenate: From table 5, we have the absorbance of homogenate as 0.42 this divided by the adsorption co-efficient gives: 0.42/20,100 = 2.1 x 10 -5 M The units for concentration are left as moles per litre (M). To get this into moles in the actual volume used (6ml not 1 litre) 2.1 x 10 -5 M x 0.006 lite = 1.3 x 10-7 M Include the reaction time of 12 minutes to give moles per minute. 1.3 x 10-7 M /12mins = 1.010-8 M -1 To determine total activity and specific activity. The total volume from table 1: for the homogenate is 12ml, however the sample used was only 0.2ml we therefore divide actual volume / used volume x concentration of H x dilution factor (20 in the case of the homogenate from table 5 values) Total activity = (12/0.2) x1.0x10-8 M -1 x 20 = 1.2 x 10 -5 M -1 specific activity = 1.2 x 10 -5 M -1/ total amount protein in homogenate from table 4 1.2 x 10 -5 M -1/864= 1.3 x 10-8 M min-1 Results for nuclei fraction: 0.13/20,100 M-1 cm-1 = 6.5 x 10-6 In 0.006 litre : 6.5 x 10-6 x 0.006 = 3.9 x 10-8 M 3.9 x 10-8 M / 12 = 3.2 x 10-9 M min-1 Total activity = 3.2 x 10-9 M min-1 x (12/0.2) x 3 = 5.8 x 10 7M min-1 Specific activity = 5.8 x 10 7/ 70.8 = 8.2 x 10 -9 M min-1 Results for mitochondria: C = 0.27/20,100 m-1 cm -1 = 1.3 x 10-5à ¢Ã¢â€š ¬Ã¢â‚¬ËœM 1.3 x 10-5à ¢Ã¢â€š ¬Ã¢â‚¬ËœM x 0.006 = 7.8 x 10-8 M 7.8 x 10-8 M / 12 = 6.5 x 10-9 M min-1 Total activity = 6.5 x 10-9 M min-1 x (12/0.2) x 20 = 7.8 x 10-6 M min-1 Specific activity = 7.8 x 10-6 M min-1/228 = 3.4 x 10-8 M min -1 Results for supernatant: C = 0.29/20,100 m-1 cm -1 = 1.4 x 10-5à ¢Ã¢â€š ¬Ã¢â‚¬ËœM 1.4 x 10-5à ¢Ã¢â€š ¬Ã¢â‚¬ËœM x 0.006 = 8.7 x 10-8 M = 8.7 x 10-8 M / 12 = = 7.3 x 10-9 M min-1 Total activity = 7.3 x 10-9 M min-1 x (26/0.2) = 9.4 x 10-7 M min-1 Specific activity = 9.4 x 10-7 M min-1/539.5 = 1.7 x 10-9 M min -1 Percentage recovery of Succinate Dehydrogenase for the fractions This is done by dividing the amount of Succinate dehydrogenase in the individual fractions by the original homogenate and then multiplied by 100 to give a percentage. Table 7: Shows the total activity for each of the fractions. Fraction Total Activity Homogenate 1.2 x 10 -5 M -1 Nuclei 5.8 x 10 7M min-1 Mitochondria 7.8 x 10-6 M min-1 Supernatant 9.4 x 10-7 M min-1 Nuclei fraction: (5.8X10-7/1.210-5 ) x 100 = 4.8% Mitochondria fraction (7.810-6/1.210-5 ) x 100 = 65% Supernatant fraction (9.410-7/1.210-5) x 100 =7.8% Relative Specific Activity of Succinate Dehydrogenase This is found by dividing the specific activity of the fractions (found above) by the specific activity of the homogenate (found above). Table 8 shows the specific activity for each of the fractions: Fraction Specific Activity Homogenate 1.4 x 10-8 M min-1 Nuclei 8.2 x 10 -9 M min-1 Mitochondria 3.4 x 10-8 M min -1 Supernatant 1.7 x 10-9 M min -1 Nuclei fraction 8.2 x 10 -9 M min-1 /1.4 x 10-8 M min-1 = 0.586 Mitochondrial fraction 3.4 x 10 -8 M min-1 /1.4 x 10-8 M min-1 = 2.429 Supernatant fraction 1.7 x 10 -9 M min-1 /1.4 x 10-8 M min-1 = 0.121 Discussion: Note: There was very little protein found in the nuclei fractions total volume, this is abnormally low since we would expect this to be higher. From the results we can determine that the this supports our prediction that The mitochondrial fraction is expected to have the highest results in specific activity due to fewer proteins present in that fraction. Organelles have been isolated from each other as seen with the differing proportions of protein found in each fraction as well as the differing values for specific and total activity calculated. However the homogenate is expected to have the highest total activity due to the higher amount of protein since all fractions are present. However since protein was found in the cytoplasm or supernatant fraction, this indicates that there was an error in the separation of the fractions as SDH is present where it usually isnt found. Succinate dehydrogenase works by transferring 2 electrons from succinate which transfers it to fumerate, which blocks the rest of the reaction when it binds to FAD, from the measurement of formazan gives the value of activity. Results show that the relative specific activity is highest in the mitochondrial fraction, as well as the percentage recovery of the fractions. Therefore demonstrating that the fractions were purified and that the homogenisation and centrifugation has been relatively successful in separating fractions. However there were some inaccuracies from the results, this includes the very low protein amount found with in nuclei fraction, this was however predicted to contain a higher amount of protein due to the nature of the organelle and the enzymes contained within it. Another inaccuracy in this experiment is that SDH was found within the supernatant. This is primarily a marker for mitochondria so would not usually be found within the cytoplasm, however due to mitochondria bursting and releasing its contents into the cytoplasm during the homogenisation stage and centrifugation the enzyme succinate dehydrogenase was present. Since the test was carried out under the same conditions in a neutral pH buffer we can conclude that this was a fair test, however is it often found that the more molecules present in a The separating of the homogenate could be improved by using another method of homogenisation, in this experiment we used a Potter Lethem homogeniser which is a glass and plastic hand homogeniser. This perhaps isnt the most accurate at pressurising cells with the force needed to accurately release cell content. Alternative homogenisers include ultrasonic and rotor based homogenisers which may provide more accurate. (www.proscientific.com) A different centrifugation method used. During this experiment differential centrifugation was used, however density gradients may provide more accurate at purifying a sample (www.coleparmer.co.uk). This method works by placing various layers after layer of gradient media such as sucrose in a tube with the heaviest layer at the bottom and the lightest at the top. The cell fraction to be separated is placed on top of the layer and centrifuged. Density gradient separation can be classified into two categories. Rate-tonal (size) separation. Isopycnic (density) in which organelles separate until their density matches the surroundings of the media in which they are. A very good medium for separating organelles is an iodinised media. (www.coleparmer.co.uk). Accuracy of the absorbance and accuracy of obtaining the protein amount. Results are slightly low indicating inaccuracy in both collecting the samples and also measuring the absorbance, this could be due to error in homogenisation and centrifugation techniques but could also be due to error in the reading of absorbance using the Spectrophotometric assay since U.V wavelength has different absorbance levels if either oxidised or reduced enzymes absorb light therefore giving innacurate indication to enzyme present (www.millipore.com) . This may affect the absorbance levels in the fractions if specific enzymes are affected thus giving an altered absorbance level and therefore undermined protein amount. Another method to measure enzyme assay could be to use a caliometric method which measures heat radiance given off instead of the absorbance levels. Some of the organelles which remain in the supernatant fraction are the smaller and less dense proportions of the cell such as ribosomes and lysosomes. Further centrifugation at a higher speed can be used to separate these smaller less dense organelles into pellets. This can also be used to further purify bacteria. In conclusion we see that as predicted, the specific activity is highest in the mitochondrial fraction and the total activity is highest in the homogenate. The % recovery of each fraction and the relative specific activity for each fraction calculated shows a higher proportion in the mitochondrial fraction also. Overall the results indicate accurate laboratory skills and results conclude what was intended, however some slight changes to laboratory equipment would mean that some of the results such as SDH found in the supernatant may not come about in a future test.

Martin Luther King Jr :: Racism Blacks America

Martin Luther King Jr Nearly three centuries ago, African slaves were brought to the New World and put into slavery. They were treated more cruelly in the United States than in any other country that had ever practiced slavery, and ever since its prohibition African-Americans have fought oppression. Martin Luther King Jr., would aid immensely in this fight. He was born in Atlanta Georgia in 1929. His father, Martin Luther King Sr. Was a Baptist minister and also preached for civil rights. By the time he was 17 he had decided to follow his fathers footsteps, so he himself was ordained as a minister. After his graduation from the Crozer Theological Seminary, when he began postgraduate work at Boston University, he studied the works of Indian nationalist Mohandas Gandhi, from whom he derived his own philosophy of nonviolent protest. He moved to Alabama to become pastor for a Baptist church. Just after he received his Ph.D. in 1955, King was asked to lead a bus boycott in Montgomery. It had been formed after Rosa Parks was arrested for refusing to give her seat to a white passenger. Throughout the 381 days which the boycott lasted, he was arrested and jailed, repeatedly threatened, and his home was bombed. The boycott ended later that year when the Supreme Court outlawed segregation in public transportation. This was his first victory and alone made Dr. King a highly respected leader. When he went to India in 1959, he studied Gandhi's principle of "Satyagraha" or nonviolent persuasion, which he planned to use for his social protests. In the following year he decided to move back to Atlanta to become copastor with his father. In 1963 he was back in Birmingham, Alabama, where he led a massive civil rights campaign, organizing drives for black voter registration, desegregation, and better education throughout the South. During that time he led the unforgettable March on Washington where he delivered his famous "I Have a Dream" speech to millions of viewers across the nation. The next year he was awarded the Nobel Peace Prize. He went on to launching his first major northern campaign in Chicago. Black Baptists were there opposing him, and a mob of club carrying Ku Klux Klan members and Neo-Nazis met his marchers. With all that he had said and done, on April 3, 1983 he said "I have been to the mountain top and seen the promise land." This was the day prior to his demise. Sadly, the following day he was shot to death in Memphis Tennessee. Nearly 500,000 of his loyal admirers attended his funeral.