Sophie Arnott Title Identification of Unknown Carbohydrates Using Various Biochemical Tests Aim To identify various unknown carbohydrates by subjecting them to a series of biochemical tests. Introduction Materials Lab coat Safety goggles Gloves 6 solid carbohydrates- Glucose, Maltose, Fructose, Starch, Sucrose, Cellulose Permanent marker Deionised water Benedict’s solution Barfoed’s reagent Diastix strips Iodine Boiled water Large beaker 12 test tubes Dimple tray Spatula Dropper pipette Experimental Method Lab coats, safety goggles, and gloves were worn. Materials were collected and laid out on the bench. The first test carried out was solubility in water. Using a spatula, a small amount of each solid carbohydrate was added …show more content…
Approximately 3ml of each solution produced in the previous test was inserted into a test tube using a dropper pipette. 4 drops of Benedict’s solution was added to each test tube and mixed well. Then each test tube was placed in a beaker containing boiling water. Any colour changes seen within 5 minutes were noted in the results table. The third test carried out was Barfoed’s test. Approximately 3ml of each carbohydrate solution was inserted into a test tube using a dropper pipette. 4 drops of Barfoed’s solution was added to each test tube and mixed well. Then each test tube was placed in a beaker containing boiling water. Any colour changes observed were noted in the results …show more content…
Discussion By reviewing the results table, all 6 types of carbohydrates can be determined. In the iodine test, a colour change was observed in carbohydrate F, but a more noticeable colour change was observed in carbohydrate E. Starch turns a dark blue-black colour in the presence of iodine, meaning carbohydrate E must be starch. In the clinistix test, solution A caused the clinistix strip to turn green-brown, meaning carbohydrate A must be glucose. The Barfoed’s solution test was carried out to determine if the carbohydrate was a reducing monosaccharide, such as glucose and fructose. After carrying out this test, carbohydrate B turned a brick-red colour, meaning it must be either glucose or fructose. However, carbohydrate A was already determined to be glucose using the iodine test, meaning carbohydrate B must be
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Data from Table 1. confirms the theory that as the concentration of glucose increases so will the absorbance of the solution when examined with the glucose oxidase/horseradish peroxidase assay. Glucose within the context of this assay is determined by the amount of ferricyanide, determined by absornace, which is produced in a one to one ratio.1 Furthermore when examining the glucose standards, a linear calibration curve was able to be produced (shown as Figure 1). Noted the R2 value of the y = 1.808x - 0.0125 trend line is 0.9958, which is statistically considered linear. From this calibration curve the absorbance values of unknowns samples can be compared, and the correlated glucose concentration can then be approximated.
These labels indicated the lactose solution that was be placed into the mini-microfuge tubes. The varying lactose ph solutions were obtained. The four miniature pipets were then used, (one per solution,) to add 1mL of the solution to the corresponding mini-microfuge tubes. When this step is completed there were two mini-microfuge tubes that matched the paper towel. Then, once all of the solutions contained their respective lactose solutions, 0.5mL of the lactase enzyme suspension was added to the first mini-microfuge tube labeled LPH4 on the paper towel, and 4 on the microfuge tube. As soon as the lactase enzyme suspension was added to the mini-microfuge tube, the timer was started in stopwatch mode (increasing.) When the timer reached 7 minutes and 30 seconds, the glucose test strip was dipped into the created solution in the mini-microfuge tube for 2 seconds (keep timer going, as the timer is also needed for the glucose strip. Once the two seconds had elapsed, the test strip was immediately removed, and the excess solution was wiped gently on the side of the mini-microfuge tube. The timer was continued for 30 addition seconds. Once the timer reached 7:32 (the extra two seconds accounting for the glucose dip), the test strip was then compared the glucose test strip color chart that is found on the side of the glucose test strip
Carbohydrate digestion begins in the saliva and stomach where alpha-amylase hydrolyses alpha-1, 4 glycosidic bonds between glucose molecules in starch, forming maltotriose, the disaccharide maltose and dextrin’s made of five to ten glucose molecules (Lim, 2007). The disaccharides sucrose and lactose come directly from food. There are four enzymes found on the brush-border membrane responsible for hydrolysing sucrose, lactose and the products of starch break down, into monosaccharaides so that they can be absorbed (Lieberman et al, 2007). These enzymes are known as glycosidases and include; glucoamylase, lactase, trehalase and sucrase isomaltase (Lieberman et al, 2007). Sucrase isomaltase...
Carbohydrate Utilization: The test result for the phenol red lactose broth was positive for acid and negative for gas. The positive result for the acid means that the organism is able to ferment the particular sugar lactose. The Durham tube did have gas in it which means the organism produced gas in the lactose broth. The rest result for the phenol red sucrose broth was negative for both acid and gas. This means the organism was not able to ferment in sucrose. The organism was also not able to produce gas in the sucrose broth.
However, there were a few trials that showed slightly different results. The reason for this could be that since this experiment is one pertaining to colour change, the change in colour may not be clear at times, making the end point difficult to discern. One reason for inconsistent colour change could be that though two drops of iodine were used each time to test the colour change, the dropper is not precise and does not have an exact gauge of how many millilitres are being used each time, affecting the uniformity of each iodine test. Also, since the amylase-starch solution was extracted manually using a dropper, there could have been inaccuracy in adding the solution to the iodine at exactly the same time for each trial.
A. M. El-Sayed, V. J. Heppelthwaite, L. M. Manning, A. R. Gibb, D. M. Suckling, J. Agric. Food Chem. 2005, 53, 953.
This includes glucose, which is produced by photosynthesis. Fructose, which is the sugar found in fruits, and galactose which is a simple milk sugar. Another example of Carbohydrates is Disaccharides, this includes maltose, sucrose, and lactose. Maltose, is grain sugar. People who have celiac disease are allergic to this because it is from the grain, and the substance does not react with the body in the right way. Sucrose is table sugar, which is used on the ordinary basis or in restaurants. Lastly for Disaccharides is Lactose, different from Galactose, which is a simple milk sugar. Lactose is more complex, giving the people allergic to milk products the name, Lactose intolerant. The last example is Polysaccharides. This includes starch, glycogen, and cellulose. Starch is most commonly known from potatoes, and can be of great use in gluten free cooking. As for glycogen , it’s found to be of many glucose linked together and cellulose is simply a plant
We were able to verify the statement by finding which macromolecules were present in the stomach contents. If he was telling the truth, the stomach contents would have protein and starches in them because the egg whites and pancake mix both consist of those macromolecules respectively. To figure out the results, a series of tests were used including different reagents and indicators. For the monosaccharides test, Benedict’s reagent was used to identify when the reaction between the sugars and solution took place. The changes in colour from blue to orange-brown indicated the various approximate sugar concentrations from 0% to more than 2%. For the starch test, Lugol’s solution which is made of iodine was used to react with the starches. In the presence of starch molecules, the solution turned blue-black. In order to test for lipids, two tests were used; the first involved Sudan IV solution which can indicate lipids that are soluble in non-polar solvents. The second was a translucence test, if lipids were present in the contents, the paper would allow the light through – be translucent. Lastly, for the protein testing, Biruet reagent’s test reacting with the peptide bond allowed the proteins to be tested producing colour changes from blue to darker purple to indicate the levels of protein
Chemistry is vitally important in our understanding physiology. The molecule of my choice for this final exam is Carbohydrates. Carbohydrates are originated as the outcome of photosynthesis, the condensation of carbon dioxide that requires light energy and chlorophyll pigment. Carbohydrates are a huge source of something called metabolic energy, which can be found in plants which help feed our animals. Carbohydrates are found in sugars and starches but they have another purpose which is called cellulose which helps transport the compound ATP. Carbs are called saccharides and if they are considered sugars. The complexity of carbohydrates which are monosaccharides and complex carbs which consist of polysaccharides disaccharides and oligosaccharides. Carbohydrates represent the main source of energy for the human body. All carbs can be broken down into sugars and absorbed into our intestines and blood stream. Your body uses the glucose formed as fuel for energy. Different carbs digest and break down at different rates. When our blood sugar levels increase our pancreas pumps insulin into our blood stream. Simple carbs turn into glucose faster where complex carbs slowly turn into glucose. The foods we eat that contain carbohydrates cause our blood sugar levels to increase, transporter proteins push the glucose into our muscles, liver cells and fat where our bodies store or end up using the glucose. The cells in our bodies can’t directly use the glucose, so it has to be converted into molecules that cells then use as an energy source. One of the most important molecule for energy storing is the adenosine triphosphate known as ATP. When our cells contain oxygen it can then turn glucose into the ATP molecules using some chemical rea...
Starch consist of mainly two parts, which are amylose and amylopectin. Amylose in starch is the main cause for the formation of a deep blue color in the presence of iodine as the iodine molecule will slips inside of the amylose coil. Iodide molecules is dissolving in water with potassium iodide because iodide is not so soluble in water. This makes a linear triiodide ion complex with is soluble that slips into the coil of the starch causing an intense blue-black colour. In this test, blue-black colour is shown and this indicates the presence of starch. Starch amylopectin does not give the blue-black colour, nor does cellulose, nor do disaccharides such as sucrose in sugar (Orhardt,
The chemistry of carbohydrates most closely resembles that of alcohol, aldehyde, and ketone functional groups. As a result, the modern definition of a carbohydrate is that the compounds are polyhydroxy aldehydes or ketones. The chemistry of carbohydrates is complicated by the fact that there is a functional group (alcohol) on almost every carbon. In addition, the carbohydrate may exist in either a straight chain or a ring structure. Ring structures incorporate two additional functional groups: the hemiacetal and acetal.