Qualitative Tests Used For Carbohydrates Biology Essay

Qualitative Tests Used For Carbohydrates Biology Essay Carbohydrates are an essential component of our diet and an important source of energy for us. Most of the things generally included in our diet have a large ratio of carbohydrates present. Also the patients suffering from Diabetes excrete huge amounts of sugar in their urine which needs to be estimated. The purity of carbohydrates can also be checked by methods which can qualitatively estimate particular sugars. Hence the need for carbohydrate estimation arose. We have been estimating carbohydrates qualitatively since school time but it was just confined to observing a colour change or a coloured precipitate to detect the presence of a carbohydrate. None of us ever thought that these qualitative tests are highly sensitive and provide much more information than just detecting the presence of a sugar. In this study conducted, two qualitative tests used for carbohydrates were studied: Benedicts test and Seliwanoffs test. Benedicts test is a test used for detecting the presence of Reducing Sugars. The test was performed using Glucose which is the most common reducing sugar. Sucrose was used as a negative control. Different concentrations of glucose were tried ranging from 1.6 M to 1.6 mM and from 4% to 0.25%.Also along with concentration the amount of sugar was varied to find the sensitivity limits and the limitations of the test. The result of Benedicts test is usually a brick red precipitate but with some modifications different colours of solutions and different amounts of precipitate could be observed with slight variation in the concentration and amount of sugar. This suggests that this test being Qualitative is not only an indicator of the presence or absence of a reducing sugar but can also be used to roughly estimate the concentration of sugar present. It can be very useful in estimation of the concentration of sugar present in the urine of diabetic patients. Seliwanoffs test is a qualitative test used for distinguishing between Aldoses and ketoses. Ketoses form a cherry red condensation product whereas Aldoses react to form a blue-green condensation product, which may further change to a peach product. The test was performed using fructose as the sample sugar. Various concentrations of Fructose were used ranging from 4% to 0.01% to find the sensitivity limits and the limitations of the test. The test appeared to be sensitive even at 0.01% showing a very faint red colour. There was a huge variation in the intensity of colour obtained at different concentrations of sugar. But the drawback of the test was that the red colour of the solution was not stable. It intensified with increase in the duration of time. 2. INTRODUCTION Carbohydrates are the most abundant bio molecules on Earth. Each year, photosynthesis converts more than 100 billion metric tons of CO2 and H2O into cellulose and other plant products. Certain carbohydrates (sugar and starch) are a dietary staple in most parts of the world, and the oxidation of carbohydrates is the central energy-yielding pathway in most non-photosynthetic cells. Insoluble carbohydrate polymers serve as structural and protective elements in the cell walls of bacteria and plants and in the connective tissues of animals. Other carbohydrate polymers lubricate skeletal joints and participate in recognition and adhesion between cells. More complex carbohydrate polymers covalently attached to proteins or lipids act as signals that determine the intracellular location or metabolic fate of these hybrid molecules, called glycoconjugates. .Carbohydrates are polyhydroxy aldehydes or ketones, or substances that yield such compounds on hydrolysis. Many, but not all, carbohydrates have the empirical formula (CH2O)n; some also contain nitrogen, phosphorus, or sulphur. There are three major size classes of carbohydrates: monosaccharides, oligosaccharides, and polysaccharides Classification Carbohydrates can be classified on the basis of the various characteristics they possess. They can be classified on the basis of the number of carbon atoms in the sugar chain, the terminal functional group in the chain, the number of sugar subunits and the reducing activity of the sugar units. Depending on various basis they are of several types: A. According to the number of carbon atoms in the sugar chain: 1. Trioses: contain 3 carbon atoms (e.g. glyceraldehyde). 2. Pentoses: contain 5 carbon atoms (e.g. ribose). 3. Hexoses: contain 6 carbon atoms (e.g. glucose). B. According to the terminal functional group in the sugar chain: 1. Aldoses: contain terminal aldehyde group (-CHO) (e.g. glucose). 2. Ketoses: contain terminal ketone group (C=O) (e.g. fructose). C. According to the number of sugar subunits: 1. Monosaccharides: Monosaccharides, or simple sugars, consist of a single polyhydroxy aldehyde or ketone unit. The most abundant monosaccharide in nature is the six-carbon sugar D-glucose, sometimes referred to as dextrose. 2. Oligosaccharides: Consist of short chains of monosaccharide units(2-10) joined by characteristic linkages called glycosidic bonds. The most abundant are disaccharides, with two monosaccharide units. e.g. sucrose (cane sugar), which consists of the six-carbon sugars- D-glucose and D fructose. 3. Polysaccharides: The polysaccharides are sugar polymers containing more than 20 or so monosaccharide units, and some have hundreds or thousands of units. Some polysaccharides, such as cellulose, are linear chains; others such as glycogen, are branched. Both glycogen and cellulose consist of recurring units of D-glucose, but they differ in the type of glycosidic linkage and have different properties and biological roles. . D. According to the reducing activity of the sugar unit: Carbohydrates that can undergo oxidation are called reducing sugars. This depends on the presence of an exposed carbonyl group. 1. Reducing sugars: Certain sugars with a free carbonyl carbon can be oxidized by oxidizing agents such as ferric (Fe3) or cupric (Cu2) ion. The carbonyl carbon (anomeric carbon) is oxidized to a carboxyl group. Such sugars capable of reducing ferric or cupric ion are called Reducing sugars. e.g. lactose, maltose. 2. Non-reducing sugars: Sugars like sucrose contain no free anomeric carbon atom since the anomeric carbons of both monosaccharide units are involved in the formation of glycosidic bond. Therefore it is a Non-Reducing sugar. 2.1 Biochemical Tests for Carbohydrates The biochemical tests for carbohydrates can be divided into two categories: Qualitative Tests- These tests are performed to detect the presence of carbohydrates in a test sample. They are also used to detect the type of carbohydrate present. There are different types of qualitative tests for different types of carbohydrates. e.g. Fehlings and Benedicts test for reducing sugars, Seliwanoffs test for ketoses, Iodines test for starch,Bials test for detecting pentoses etc. They are not very sensitive as compared to quantitative tests and cannot estimate the exact amount of carbohydrates present but show some difference in the observation with variation in the amount of carbohydrate hence, can be used to make a rough estimate of the amount of sugar present. Quantitative Tests- These tests are the advanced form of qualitative tests and can be used to estimate the amount of carbohydrate present in a given sample. These tests use particular chemicals which form coloured complexes with sugars which can then be read at certain wavelengths using a spectrophotometer. Their absorbance can then be used to estimate the exact amount of carbohydrate present in the sample. e.g. Anthrone test, DNS Method, Phenol- Sulphuric Acid Method etc. 2.11 Qualitative Test Flow Chart for classifying an unknown carbohydrate A. Molisch Test Molisch test is used to distinguish between carbohydrates and non- carbohydrates. It is the preliminary test used to detect the presence of carbohydrates in a sample. Principle It uses concentrated sulphuric acid as a Dehydrating acid which dehydrates all carbohydrates to form Furfural or 5-hydroxymethylurfural from reaction of sulphuric acid with pentoses and/or hexoses. These products condense with ÃŽ ±-naphthol to yield a purple condensation product. B. Iodine and Potassium Iodide Test This is a test used particularly to detect starch and glycogen. Starch gives a blue-black colur with potassium iodide whereas glycogen gives reddish-brown colour. Principle Starch contains ÃŽ ±-amylose, a helical saccharide polymer, and amylopectin. Iodine forms a large complex polysaccharide with the ÃŽ ±-amylose helix, producing a blue-black colour. Simple Oligosaccharides and Monosaccharides do not form this complex with Iodine. Thus, the I2/KI test can be used to distinguish starches from other carbohydrates. C. Bials Test Bials test is used to distinguish between pentoses and hexoses. Principle This test uses concentrated hydrochloric acid as the dehydrating acid and orcinol with a trace of iron(III) chloride as the condensation reagent.. Pentoses subjected to the test yield a blue or green condensation product, while hexoses yield a muddy brown to grey condensation product. Pentose Dehydration Product Blue or Green condensation product (Furfural) Hexose Dehydration Product Muddy brown-Grey condensation product (5-hydroxymethylfurfural) D. Seliwanoffs Test Seliwanoffs test is used to distinguish between aldoses and ketoses. Principle This test uses 3N hydrochloric acid as the dehydrating agent as resorcinol as the condensation reagent. When mixed with Seliwanoffs Reagent, Ketopentoses react within 2 minutes to form a cherry red condensation product. Aldopentoses react after 2 minutes to form a blue-green condensation product, which may further change to a peach product. Fructose Hydroxy-methyl Cherry-Red Complex Furfural Identifying Reducing Sugars All mono and disaccharides with a free aldehyde or keto group act as reducing agents in alkaline solutions. The reducing properties of sugars are dependent upon the presence of actual or potential aldehyde or ketone groups. The enolization of sugars under alkaline conditions is an important consideration in reduction tests. The ability of a sugar to reduce alkaline test reagents depends on the availability of an aldehyde or keto group for reduction reactions. A number of sugars, especially disaccharides or polysaccharides have glycosidic linkages which involve bonding between each group, and hence there is no reducing group on the sugar; such as the case for sucrose, trehalose, inulin, glycogen, starch, and dextrin. In the case of reducing sugars, the presence of alkali causes extensive enolization especially at high pH and temperature. This leads to a higher susceptibility to oxidation reactions than at neutral or acidic pH. These sugars, therefore, become potential agents capable of reducing Cu+2 to Cu+, Ag+ to Ag and so forth. Reducing sugars can react with many different oxidizing agents. Fehlings test, Benedicts test and Barfoeds test have been used to distinguish between monosaccharides and disacc harides Monosaccharides fluctuate between a ring open form and a ring closed form. The ketone (-C=O) group, for Fructose and the aldehyde group (-CHO), for Glucose in the ring open forms can be reduced using these tests. Some sugar units in disaccharides also fluctuate between a ring open form and a ring closed form. These disaccharides are also reducing sugars because the ring open form has a ketone or aldehyde to react. Sucrose is one of the few disaccharides that do not have a ring open form so it is a non-reducing sugar.  ­Ã‚ ­Ã‚ ­ Ring Open Fructose and Ring Closed Fructose Ring Open Glucose and Ring Closed Glucose Reducing Sugars are oxidized by copper (II) ions. Benedicts reagent and Fehlings Reagent are mildly basic solutions whereas Barfoeds Reagent, a mildly acidic solution. The presence of red copper (I) oxide precipitate indicates that the saccharide has reduced the copper (I) ions. E. Fehlings test Principle Fehlings test uses a mixture of fehlings solution A and B. Fehlings solution A consists of copper(II) sulphate dissolved in dilute sulphuric acid. Fehlings solution B is sodium potassium tartarate dissolved in dilute NaOH. Both the solutions are mixed in equal proportions and used as fehlings reagent. This reagent is used as a general test for detecting reducing sugars. A reducing sugar reduce copper(II) ions to copper(I) oxide, forming a red precipitate. CuSO4Cu++ + SO4 2 Cu++  + Cu+ Glucose (Reducing Sugar) Cu+Cu2O (red precipitate) Cuprous Oxide F. Benedicts test Principle Benedicts test uses a mixture of copper(II) sulphate, sodium citrate, and sodium carbonate in a mildly basic solution. This reagent is used as a general test for detecting reducing sugars. A reducing sugar reduce copper(II) ions to copper(I) oxide, forming a red precipitate. CuSO4Cu++ + SO4- (Copper Sulphate) (Cupric Ion) (Sulphate Ion) 2 Cu++  + Cu+ Glucose (Reducing Sugar) Cu+Cu2O (red precipitate) Cuprous Oxide G. Barfoeds Test Benedicts test gives positive test results for all reducing sugars. However, not all reducing sugars react at the same rate. With different oxidizing agents, disaccharides are considerably less reactive compared to monosaccharides. A positive Barfoeds test result is similar to that observed with Benedicts solutions. Monosaccharides give positive Barfoeds test results within 2-3 minutes, while disaccharides do not react under the same conditions. Principle Barfoeds test uses copper(II) ions in a slightly acidic medium. If the reaction time is carefully monitored, this test can be used to distinguish reducing monosaccharides from reducing disaccharides. Reducing disaccharides cause the formation of copper(I) oxide after approximately 10 minutes. (CH3COO) 2Cu + 2H2O 2 CH3COOH + Cu(OH)2 Cu(OH)2 CuO+ H2O 2CuO  +Cu2O (red precipitate)   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (Glucose) Reducing Sugar 2.12 Quantitative Tests A. Determination of Total Carbohydrate by Anthrone Method Principle Carbohydrates are first hydrolysed into simple sugars using dilute hydrochloric acid. In hot acidic medium glucose is dehydrated to hydroxymethyl furfural. This compound forms with anthrone a green coloured product with an absorption maximum at 630 nm. HCl anthrone Carbohydrate furfural/hydroxymethyfurfural Green product (630 nm) B. Phenol Sulphuric Acid Method for Total Carbohydrate Principle In hot acidic medium carbohydrates are dehydrated to furfural/hydroxymethyl furfural. This forms a green coloured product with phenol and has absorption maximum at 490 nm. H2SO4 phenol Carbohydrate furfural/hydroxymethylfurfural Green product (490 nm) C. Determination of Reducing Sugars by Nelson-Somogyi Method The Nelson-Somogyi method is one of the classical and widely used methods for the quantitative determination of reducing sugars. Principle The reducing sugars when heated with alkaline copper tartarate reduce the copper from the cupric to cuprous state and thus cuprous oxide is formed. When cuprous oxide is treated with Arsenomolybdic acid, the reduction of molybdic acid to molybdenum blue takes place. The blue colour developed is compared with a set of standards in a colorimeter at 620 nm. Cu2O+ Arsenomolybdate Molybdenum Blue (Cuprous Oxide) (500 nm) D. Estimation of Reducing Sugar by Dinitrosalicylic Acid Method This method is an alternative to Nelson-Somogyi method. It is a simple, sensitive and adoptable method during handling of a large number of samples at a time. However,  enzymatic  methods are usually preferred to DNS due to their specificity. Principle 3,5-Dinitrosalicylic acid   is an  aromatic compound  that reacts with reducing sugars to form  3-amino-5-nitrosalicylic acid, which absorbs  light  strongly at 540  nm. 3,5-Dinitrosalicylic acid 3-amino-5-nitrosalicylic acid E. Determination of Glucose by Glucose Oxidase Method Glucose is a widely distributed simple sugar with an active aldehyde group. Estimation of glucose by glucose oxidase gives the true glucose concentration eliminating the interference by other reducing sugars. Principle Glucose oxidase catalyses the oxidation of alpha-D-glucose to D-glucono-1, 5 lactone (gluconic acid) with the formation of hydrogen peroxide. The oxygen liberated from hydrogen peroxide by peroxidase reacts with the O-dianisidine and oxidises it to a red chromophore product. Glucose + O2 H2O2 + Gluconic Acid (glucose oxidase) H 2O2 + O-dianisidine Red-coloured product (peroxidase) (540 nm) 3. MATERIALS REQUIRED I) Stock Solutions Glucose 1.6 M Glucose 4% (w/v) Sucrose 0.1 M Fructose 4% (w/v) II) Reagents Benedicts Reagent Step 1-Dissolve 173 g sodium citrate and 100 g sodium carbonate in about 500 mL water. Step 2-Heat to dissolve the salt Step 3-Dissolve 17.3 g copper sulphate in about 100 mL water and add it to the above solution with stirring and make up the volume to 1 L with water. Seliwanoffs Reagent Dissolve 0.05 gm resorcinol in 3N hydrochloric Acid. III) Miscellaneous Water Bath Test Tubes Clamps Conical Flasks Beakers Containers Test tube holders 4. METHODOLOGY 4.1 Benedicts Test Step 1- Pipette out 1 ml of glucose solution in some test tubes so that there is a triplicate for each set. Step 2- Pipette out 1ml of Distilled Water in one test tube which serves as blank and 1 ml of Sucrose solution (0.1M) in another which serves as a negative control. Step 3- Add 2 ml of Benedicts reagent in all the test tubes. Step 4-Transfer all five tubes to the boiling water bath provided and record the time for the appearance of precipitate. Step5- Make a subjective analysis of the colours observed. A scale of + to +++++ can be used to record the depth of the colour, from lightest to darkest. 4.11 Effect of variation in Carbohydrate Concentration (in M) The concentration of glucose was varied from 1.6 M to 1.6 mM keeping the reaction volume constant to 3 ml. The upper and the lower sensitivity limits and the optimum molar concentration of glucose was found for the test through subjective analysis. 4.12 Effect of Reaction Volume The reaction volume was reduced from 3 ml to 1.5 ml for all the concentrations of glucose ranging from 1.6 M to 1.6 mM to find any difference in the sensitivity range and the optimum molar concentration of glucose for the test. 4.13 Effect of variation in Carbohydrate Concentration (in %) The concentration of glucose was varied from 4% to 0.25%. Also the reaction volume was changed and the analysis was performed in two sets. The volume of reagent used was 5 ml whereas the volume of samples all concentrations in Set A and B were 50ÃŽ ¼l and 25ÃŽ ¼l respectively. 4.14 Effect of variation in Sample Volume The volume of glucose was varied for the same concentrations 4% to 0.25% to see the changes in the colour of solution obtained and at the same time find the upper and lower limits at which the test still remains sensitive. The analysis was performed in 6 sets with the following volumes of glucose: 200ÃŽ ¼l, 100ÃŽ ¼l, 50ÃŽ ¼l, 25ÃŽ ¼l, 12.5ÃŽ ¼l and 6.25ÃŽ ¼l. 4.15 Effect of Reaction Volume on the results obtained. Of the various sets tried 5 ml of Benedicts reagent and 200ÃŽ ¼l of sample gave the best results. To verify the consistency of results obtained the reaction volume was reduced. The analysis was performed in two sets. Set A with 2.5 ml of reagent and 100ÃŽ ¼l of sample and Set B with 1.25 ml of reagent and 50ÃŽ ¼l of sugar sample. 4.2 Seliwanoffs Test Step 1- Pipette out 1 ml of fructose solution in test tubes so that there is a triplicate for each set. Step 2-Pipette out 1ml of Distilled Water in one test tube which serves as blank. Step 3- Add 2 ml of Seliwanoffs reagent in all the test tubes. Step 4-Transfer all tubes to the boiling water bath for 2.5 mins. Step 5- Make a subjective analysis of the colours observed. A scale of + to +++++ can be used to record the depth of the colour, from lightest to darkest. 4.21 Effect of variation in carbohydrate concentration (in %) The concentration of fructose was varied from 4% to 0.015% keeping the reaction volume constant to 3 ml. The upper and the lower sensitivity limits and the optimum concentration of fructose were found for the test through subjective analysis. 5. OBSERVATIONS 5.1 Benedicts Test 5.11 Effect of variation in Carbohydrate Concentration (in M) A brick red precipitate was observed for all the concentrations of sample ranging from 1.6 M to 3.125 mM. But the last concentration of 1.6 mM showed a negligible amount of precipitate. Also once centrifuged the supernatant was found to be colourless for concentrations ranging from 1.6 M to 0.1 M. The supernatant was observed to be blue in concentrations ranging from 50 mm to 1.6 mM. Glucose (M) Colour Intensity 1.6 0.8 0.4 0.2 0.1 0.05 0.02 0.012 0.006 0.003 0.001 +++ ++++ ++++ +++++ ++++++ +++++ ++++ +++ ++ + 5.12 Effect of variation in Reaction Volume A brick red prcipitate was observed for all the concentrations of sample ranging from 1.6 M to 6.25 mM. Concentrations 3.125 mM and 1.5625 mM showed a negligible amount of precipitate. For concentrations 6.25 mM to 0.1 M there was an increase in the amount of precipitate observed with the highest amount formed in 0.1 M of sample. For the next two concentrations i.e. 0.2 M and 0.4 M the amount of precipitate formed was almost equal but again reduced for 0.8 M and 1.6 M glucose sample. Also after centrifugation the supernatant was found to be colourless for concentrations ranging from 1.6 M to 0.1 M. The supernatant was observed to be increasingly blue in concentrations ranging from 50 mm to 1.5625 mM. Glucose (M) Colour Intensity 1.6 0.8 0.4 0.2 0.1 0.05 0.02 0.012 0.006 0.003 0.001 +++ ++++ +++++ +++++ ++++++ ++++ +++ ++ + 5.13 Effect of variation in carbohydrate concentrations (in %) There was a brick red precipitate observed in for all the concentrations of sample ranging from 0.25% to 4% in both the sets. The highest amount of precipitate was observed for 1% sample but there was no consistency in results seen. Glucose (%) Set Set B 4.0 2.0 1.5 1.0 0.5 0.25 +++ + ++++ + ++ + +++ 5.14 Effect of variation in Sample Volume There was a variation in the colours obtained at different concentrations and volumes of sugar sample used. But sets with 12.5ÃŽ ¼l and 6.25ÃŽ ¼l of sugar did not show any noticeable changes in colour. Glucose (%) Set A Set B Set C Set D Set E Set F Set B Set C Set D Set E Set F 4.00 2.00 1.00 0.50 0.25 reddish brown brown green greenish blue dull blue brown green greenish blue dull blue green greenish blue dull blue blue blue greenish blue dull blue blue blue blue dull blue blue blue blue blue blue blue blue blue blue 5.15 Effect of reduction in the reaction volume There was no change in the observations due to reduction in the reaction volume. Glucose (%) Set A Set B 4.0 2.0 1.0 0.5 0.25 reddish brown brown green greenish blue dull blue reddish brown brown green greenish blue dull blue 5.2 Seliwanoffs Test 5.21 Effect of variation in carbohydrate concentration (in %) A cherry red colour is observed for all the concentrations of fructose used but the intensity of colour obtained decreases with decrease in concentration. The lowest concentration used (0.015%) has a faint red colour. Also the colour of the solution intensifies with time if kept after boiling. Fructose (%) Colour Intensity 4.00 2.00 1.00 0.50 0.25 0.12 0.06 0.03 0.01 +++++++++ ++++++++ +++++++ ++++++ +++++ ++++ +++ ++ + 6. RESULTS AND DISCUSSION 6.1 Benedicts Test 6.11 Effect of variation in Carbohydrate Concentration (in M) It can be observed that 0.1 M is the optimum concentration of sugar for Benedicts reaction with the reaction volume of 3 ml since the highest amount of precipitate is formed at 0.1 M. Also the supernatant obtained after centrifugation is colourless which suggests that the reaction is completed and there is no unused reagent left. Concentrations less than 0.1 M show decreasing amounts of precipitate and the colour of the supernatant is also increasingly blue. This suggests that as the concentration of sugar is lowered the amount of unreacted Benedicts reagent increases which leaves the solution blue even after the reaction completes. 1.6 mM sugar sample shows a negligible amount of precipitate formation which suggests that the reaction is not sensitive for concentrations lower than 1.6 mM. For concentrations higher than 0.1 M the amount of precipitate formed again decreases with increase in concentration which suggests that the concentration is too high as compared to the amount of reagent used and hence no more precipitate is formed after the reaction completes. 6.12 Effect of variation in Reaction Volume The reaction volume was reduced to half but has no effect on the results of the experiment. 0.1 M is the optimum concentration of sugar for the reaction with the reaction volume of 3 ml since the highest amount of precipitate is formed at 0.1 M. Also the supernatant obtained after centrifugation is colourless which suggests that the reaction is complete and there is no unused reagent left. Concentrations less than 0.1 M show decreasing amounts of precipitate and the colour of the supernatant is also increasingly blue. This suggests that as the concentration of sugar is lowered, the amount of unreacted reagent increases which leaves the solution blue even after the reaction completes. 3mM and 1.6 mM sugar samples show a negligible amount of precipitate formation which suggests that the reaction is not sensitive for concentrations lower than 3 mM with a reaction volume of 1.5 ml. For concentrations higher than 0.1 M, the amount of precipitate formed again decreases with increase in concentration which suggests that the concentration is too high as compared to the amount of reagent used and hence no more precipitate is formed after the reaction completes. 6.13 Effect of variation in carbohydrate concentrations (in %) The highest amount of precipitate was formed in 1% sugar sample but there was no consistency in the observations due to incorrect preparation of reagent. During the preparation of reagent instead of mixing Sodium citrate and Copper Sulphate together in hot water they were dissolved separately and then mixed. Also the solution was not made up to 500 ml with distilled water rather measured amount of water was added to the solution to make it 500 ml which made the solution dilute and hence gave incorrect results. 6.14 Effect of variation in Sample Volume Different volumes of sugar were tried for all the different concentrations. There was a variation in the colours obtained. 200ÃŽ ¼l of sugar reacted with 5 ml of reagent showed maximum variation in colours at different concentrations: Reddish Brown, Brown, Green, Greenish blue and dull blue obtained at 4%, 2%, 1%, 0.5% and 0.25% respectively. Sets with 12.5ÃŽ ¼l and 6.25ÃŽ ¼l of sugar volume did not show any noticeable changes in colour which suggest that the volume of sugar solution was not enough for the reaction to take place. 6.15 Effect of reduction in the reaction volume Reduction in the reaction volume made no difference to the variation in colours obtained at different concentrations of sugar which suggests that Benedicts reagent and glucose can be reacted in this ratio in any volume to estimate the concentration of glucose present in an unknown sample. 6.2 Seliwanoffs Test 6.21 Effect of variation in carbohydrate concentration (in %) A cherry red colour is observed for all the concentrations of Fructose used but the intensity of colour obtained decreases with decrease in concentration. The highest intensity is observed at 4% sugar concentration. 0.015% which is the lowest concentration of sugar used gives a very faint red colour which cannot be taken as pos

Nu Shu – The Women’s Writing of China

Nu Shu, also known as the women's writing of China, was a major part of Chinese women's lives throughout the 20th century. Unlike any other writing, it is the only known hidden written language. Women used Nu Shu as a way to escape from the oppressive outside world and enter into a peaceful state of mind. Life was hard enough for women; it's scary to think how hard Nu Shu was probably the most commonly valued thing for women in China during this time period. It was valued so much because it was used to share women's miseries. China was ruled by men, and women were nothing more than ousewives and sometime field workers. What made it so special was that only women knew about it. It was a written language expressed by songs and stories. Any other language besides Chinese was forbidden by Emperors. Women couldn't use any form of education, so it had to be formed in secret. Having been something only women knew, it was an easy way for them to express their hardships and sufferings. Every woman at that time was going through the same thing, so it was seen as the easiest way for women to let out their feelings. Males dominated society completely, and Nu Shu was the nly true form of power that women had. If it had been leaked to the public, not only would it have been banned, but many women would have been sent to jail and killed if found using it. Women were beaten and abused to the point where a good day in marriage was a day you cried. Marriages were always arranged, and many women didn't even have feelings towards their husbands. They had to put up with the abuse and couldn't complain. At any point in time, a man could tell his wife what to do and when to do it. Women had no say in the government, their marriage, and in everyday society. The only time they could speak freely was when writing in Nu Shu. Their only audience willing to listen was other women, and Nu Shu was the only way to get in touch with other women without anyone finding out. Whether or not Nu Shu was good or bad is often debated. I happen to think it was good for many reasons. Women weren't educated in any way. Nu Shu was the closest thing they had to education. With education comes power, and that was exactly what women needed. In a time when men ruled society, power is everything. While it wasn't power that everyone recognized, it helped women have better mindsets. In a way, it was creating a more equal society for these women. Equal was definitely something the Chinese culture wasn't centered around, but it was something all women strived for one day. It was often believed that Nu Shu taught women to accept their suffering, but I actually think it was the opposite. No women would ever accept that feet binding were okay, or that the beatings from their husbands should be allowed. Instead, they learned how to cope with these struggles. Knowing how to handle yourself in bad times is a very good quality to have. When thrown a curveball in life, instead of sulking about t, the better thing to do is to take a step back and learn how to deal with it. I think that is something people in Western society do well and in the long run made the Chinese women stronger. Unfortunately, the last living person proficient in Nu Shu died several years ago. I think it's a shame that Nu Shu is closer to being extinct. While the actual writing itself may have no significance to anyone in today's world, I think a great lesson can be learned from it. It's fascinating how long women were successful in keeping it a secret, and overall made the Chinese women stronger people.

The True Meaning of Cultural Issues Essay Topics

The True Meaning of Cultural Issues Essay Topics The 5-Minute Rule for Cultural Issues Essay Topics You may find there's a compelling argument for learning another language after all! There's a good deal of information to process in the actual planet, and to be mindful of at least some of it can make a significant difference. If you can select the matter all on your own, it's possible to develop the issue of interest! Normally, the practice of media globalization can't be stopped quickly since it is a procedure or the end result of some new communications technology. The Good, the Bad and Cultural Issues Essay Topics Banking essays can be real fun to play with if you've got an exhaustive understanding about the discipline and have keen interest in writing, so should you believe you cannot write decent banking essays than again you're mistaken. Colleges want to get a feeling of maturity and introspectionpinpoint the transformation and demonstrate your private growth. To compose a strong argumentative essay, students should start by familiarizing themselves with a number of the common, and frequently conflicting, positions on the research topic so they can write an educated paper. Furthermore, summarative assessment may also be incorporated, whereby students can take part in differentiation assessment program. Hence, if you believe banking essays are boring just like your company studies are, then you're probably wrong here. Moreover, in-text citations will present your awareness of the various papers formats. Ensure you give clear explanations of the things on your list too. You ought to back up your viewpoint with well-researched facts and data too. Application essays about challenges reveal how you respond to difficulty to individuals who are really interested in how you are going to take care of the subsequent four years by yourself. Naturally, the area of business is quite wide. Commonly it provides the info about current affairs it spreads throughout the world. F. Bacon The main intention of the capital isn't to get as much money as possible, yet to make sure that money produces a better life. Though you're just beginning to compose essays, you shouldn't struggle attempting to think of something to discuss. The ideal thing is to decide on a topic that will provide you with an opportunity to present new ideas or a fresh perspective on a problem. Naturally, you can select any topic, nobody could ever know that you're describing experience that you never actually had, but don't forget that it is always simpler to tell the truth than to invent lies. When you're picking your topic, remember that it's much simpler to write about something which you presently have interest ineven in case you don't know a good deal about it. The Honest to Goodness Truth on Cultural Issues Essay Topics Researching the topic will permit you to find out more about what fascinates you, and should you pick something you really like, writing the essay will be more enjoyable. The very best topic for your essay is one which is aligned with your subject of study. Still, figuring out the very best topic for your essay isn't your only concern for a student. Deciding upon the proper topic for a persuasive speech can be not such an easy matter to do as it might seem. So you don't actually wish to locate a topic! Try out another topic and do the exact same 5-minute writing test till you locate a topic you know you can readily write on. If you get to select your own topic, that's good. Therefore, the topic ought to be debatable! When you are finished with your essay, you must not simply check it for spelling and grammatical errors, but nevertheless, it also has to be checked for logical fallacies. If it's necessary to write your whole essay in 1 day, do your very best to give yourself breaks so you don't burn out. So without further ado, below are some effective writing tips to produce your common app essay stick out! By abiding By the above-given ideas you will readily attain an impactful argumentative essay. Whatever college essay topic you select or are assigned, the trick is to compose a fantastic stand-out essay. It's important to select debatable argumentative essay topics as you need opposing points that you may counter to your own points. The reader ought to take the author's side by the close of the reading. Ask your teacher if you have any questions about the subject you have selected. Well, the response isn't too obvious here. Your response shouldn't be a book report. The college essay is among the main elements of your college application. To defend your subject, you can recall the effect of overloaded schedule on college grades. The success of a research paper mostly is contingent on the topic, which is why many of time is spent searching for the best research paper topics for college students. A college essay topic may or might not be freely dependent on the student based on the course and the professor.

Abolitionist And The Civil War - 995 Words

Abolitionist and the Civil War Three decades before the Civil War, a movement wanted Emancipation for all slaves. The Abolitionists were wanting slavery to be abolished due to moral causes along with courage. Tis movement became and Evangelical crusade in the 1830s. Their main focus and pus was to end the sin-filled behaviors against the slaves everywhere. Personal freedom was exceedingly important and a belief that, â€Å"all men are created,† (Abolitionist Movement,† History, N.p.,n.d.). There were religious, political, radical and militant abolitionists. The religious abolitionists tried to get religious institutions as their allies. They gained the Methodist, Baptist and the Presbyterian groups for their anti-slavery movement. All of this brought dissension among the Baptist and Methodist. The northerners were protested against for allowing slave owners into the house of worship. An â€Å"American Missionary Association,† was created by the abolition ist after various groups resisted the movement. Political abolitionist started placing their focus on â€Å"political antislavery reform,† (â€Å"AAP Brief History,† N.p, n.d.). Petitions were gathered and many politicians were questioned on their stance on slave issues. The government chose to not respond, the abolitionists then formed the Liberty party. The Liberty parties were charged with emancipation where they expected immediate abolishment of slavery. Their stance was on of morals and political grounds for their pushes.Show MoreRelatedRole of the Mexican-American War in Bridging the Gap between the Abolitionist Movement and the Civil War815 Words   |  3 PagesABOLITION TO SECESSION VIA MEXICAN AMERICAN WAR 1 The Mexican-American War (1846-1848) marked a midpoint in U.S. history that bridged the gap between the abolitionist movement and the Civil War, which is not always recognized but is in some ways still with us today. Teacher Eric Burnett, for example, outlines a long list of catalysts leading up to the Civil War itself but omits the Mexican-American war even though the Civil War catalysts go back through the 1840s all the way back to Eli WhitneyRead MoreThe American Abolitionists Book Review Essay1214 Words   |  5 PagesHarrold Stanley, American Abolitionists is a book that scrutinizes the movement of abolishing slavery in the United States. It examines the movement from its origin in the 18century in the course of the Civil War and the elimination of slavery in 1856. American Abolitionists book focuses on the American Abolitionists who struggled to end slavery and advocated for equal rights for all African Americans in the United States. Harrold mainly focuses his book on the ab olitionist movement and the effectRead MoreThe Civil War Of The United States1440 Words   |  6 Pages The Civil War was one of the most deadly wars the United States ever fought it was fought between the North and South and to this day still leaves a big mark on the history of the United States. Though the Civil War seemed to be clear cut on what happened during the conflict its cause is to this day seemingly undecided. Was it the simple piece of legislature called the Kansas-Nebraska act that started it or the election of the United States president Abraham Lincoln that caused the turmoil? EitherRead MoreFrederick Douglass : African American Freedom Struggle888 Words   |  4 Pageshelp of the abolitionist movement. Before becoming a famous spokesman Douglass was just like every other African American slave, attempting to find a way to freedom. Douglass’ runaway slave status quickly changed when abolitionist bought his freedom in hopes to strengthen the abolitionist movement. Since abolitionists were able to recognize Douglass’ intellectual abilities it made him a ke y aspect towards the success in the abolitionist movement, African American community, and the Civil War. BeforeRead MoreCivil War Essay: The Major Contributing Factors to the Civil War888 Words   |  3 PagesIf asked, most people would blame as the cause of the civil war the issue of slavery. This is understandable; many people in the U.S. at the time were against slavery, going to far as to help runaway slaves escape to the free north. But, while slavery at face value was a major factor, international politics and economics played a major role. Several factors, including the election of Lincoln, the raid on Harper s Ferry, the Dred Scott decision, and, most importantly, the fugitive slave law, contributedRead MoreCause Of The Civil War On America1290 Words   |  6 Pages1301 Professor Harris December 3, 2015 Causes of the Civil War Lasting from 1861-1865 The Civil war: one of the most bloodiest and alienated wars in the American History has had a tremendous impact on our past society, and modern as well. In the early 1800’s the United States accomplished harmony, alliance, and unification, eventually causing sectionalism to flourish. This controversy led to the famous bloody war, known as the Civil war. While the south wanted to separate, and become one, theRead MoreAnother Leader, James Birney, Was A Powerful Abolitionists1550 Words   |  7 Pages Another leader, James Birney, was a powerful abolitionists leader and â€Å"he believed that political action and the power of religion were the keys to ending slavery,† and his proposal, â€Å"proposed measures that would allow the legislature to emancipate slaves and prohibit selling slaves brought into the state,† allowed for him to be known as, â€Å"one of the nation’s most prominent abolitionists† (American Experience†). James Birney was also the Liberty Party’s presidential candidate during the 1840 toRead MoreThe Events That Caused The Civil War1688 Words   |  7 Pages The Events That Caused the Civil War One could argue that the true causes of the Civil War were states’ rights and taxations. Although this played a large part in the start of the Civil War, slavery was the ultimate factor that led to this event in history. Economic and social differences between the north and the south, fights between slave and non-slave proponents, the growth of the abolition movement, and the election of Abraham Lincoln are all events having to do with slavery in the United StatesRead MoreThe War Of The American Civil War1618 Words   |  7 Pages A Civil War is a battle between the same citizens in a country. The American Civil War was fought from 1861 to 1865 to determine the independence for the Confederacy or the survival of the Union. By the time Abraham Lincoln was elected president in 1861, in the mist of 34 states, the constant disagreement caused seven Southern slave states to their independence from the United States and formed the Confederate States of America. The Confederacy, ge nerally known as the South, grew to include elevenRead MoreSlavery And The Civil War958 Words   |  4 Pagessupporting slavery, into a head on collision course: the Civil War. Slavery and the Civil War are more intertwined than face value would ever suggest. For some, the major cause of the Civil War was about slavery, this should not be a shock to anyone, but sadly, it commonly is misinterpreted. According to an article by James Illingworth titled, â€Å"Slavery and the origins of the Civil War†, â€Å"One hundred fifty years after it began, the Civil War remains one of the most misunderstood episodes in American