Vanessa Mendez Unknown# 26 Lab Practicum Report Results: The carbohydrate procedure was done due to the fact that my unknown represented a carbohydrate result by doing the Molisch Test. A TLC test was done to verify it was not an amino acid which proved to be negative. The Mucic Acid, Molisch, Bial's, Seliwanoff, Benedicts, and Barfoed's test was done to see the characteristics to help identify my unknown. Mucic acid test contained 100 mg of unknown, and 1 ml of HNO3 , and water which were heated for a hour. Bial's had 0.5 ml of unknown, and 1 ml of Bial's reagent heated to test for pentoses. Seliwanoff's tests for fructose or sucrose, by using 0.25 ml of unknown and the 1 ml reagent heating after. Benedicts test for monosaccharide's, …show more content…
and lactose by using 0.2 ml an 1 ml of the reagent. Barfoed's test forms a red color precipitate in the monosaccharide's by using 0.2 ml of unknown, and 1 ml of the reagent. Table 1 shows the general expected results comparing it to table 2 which are the results that I got by doing the carbohydrate tests. Table 1: General expected Results Carbohydrate Mucic Acid Molisch Bial's Seliwanoff Benedicts Barfoeds Fructose - Band Light purple bottom Dark brown Deep red Red precipitate Red precipitate Galactose White precipitate Light pink bottom purple band Dark brown No color Red precipitate Red precipitate Glucose No presence of precipitation Band clear bottom Dark brown No color Red precipitate Red precipitate Glycogen - Band clear bottom Dark brown No color - - Lactose White precipitate Band clear bottom Dark brown No color Red precipitate - Starch - Band clear bottom Dark brown No color - - Sucrose - Purple band Dark brown Deep red - - Xylose - Purple band Dark blue No color Red precipitate Red precipitate Table 2: Results observed by doing the carbohydrate tests on my unknown Mucic Acid Formed a precipitate, white precipitate settled on the bottom, positive test Molisch Formed purple on the bottom, positive test Bial's After five minutes of boiling it turned dark brown, and remained the same color, negative test for xylose Seliwanoff No color, clear. Negative result for fructose or sucrose Benedicts Red precipitate, positive test Barfoeds Slight red on the bottom, positive test According to the results stated in table 2 my unknown is Galactose.
The observed results matched the general expected results of Galactose. Music acid formed a white precipitate. Bial's and Benedicts test had red precipitate. Seliwanoff test had no color. Bial's test had a dark brown color. Looking into the results obtained by doing the test Galactose was the adequate choice to what my unknown was. Discussion: Essentially my first test was the TLC test to verify that my unknown was not a amino acid which proved to be negative. After seeing this result I did the Molisch to test that the unknown was a carbohyrate. The Molisch test was positive which from this step the rest of the carbohydrate tests were done to find which carbohydrate it was. The Mucic test was the crucial one since it is only positive for Galactose, and lactose. When performing this test on my unknown it was positive. Seliwanoff had no color which served as a negative result for Fructose, and Sucrose. Bial's test was negative for a dark blue color which reflected that it wasn't Xylose. In Barfoed's test there was a positive red color which reflected that it was not lactose either. Looking at the data table with the observed results it made sense that the unknown was
Galactose.
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.
We actually saw this change occur by watching the RER values increase. At the 2:30 mark Kerbi was using 100% fats as her fuel source with an RER of .75. One minute later, at an RER of .80 she was using 50% fat and 50% carbohydrates. In between minutes 6:30 with and RER of .99 and less than the 7:00 mark with an RER of 1.04 she was using primarily 100% carbohydrates as her fuel source. Lactate began accumulating in Kerbi’s blood at the 7:00 mark with an RER of 1.04, a speed of 3.4 and a grade of 14. I know this because her RER was above the 100% carbohydrate level of 1.00, and this is also the time at which she felt uncomfortable to the point that the test
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
When the solution remains the same, it means the solution is negative control and does not have sugar. The presence of starch can be detected by using the Lugol’s iodine solution. If the unknown A, B, C milk samples turn to a dark blue color during the Lugol’s test, then these samples are positive control and also contain starch in them. But if the solutions turn to yellowish brown, it means these solutions are negative control
b) Comprehensive diagnostic chemistry panel with significantly increased amylase (1626 with normal being 300-1100 U/L), total
To uncover organic compounds like carbohydrates, lipids, proteins and nucleic acid, by using tests like Benedict, Lugol, Biuret and Beta Carotene. Each test was used to determine the presents of different organic molecules in substances. The substances that were tested for in each unknown sample were sugars, starches, fats, and oils. Moreover, carbohydrates are divided into two categories, simple and complex sugars. Additionally, for nonreducing sugars, according to Stanley R. Benedict, the bond is broken only by high heat to make make the molecules have a free aldehydes (Benedict). As for Lipids, there are two categories saturated and unsaturated fats. One of the difference is that saturated fats are mostly solids and have no double bond (Campbell Biology 73). The Beta Carotene test works by dissolving in a lipid, thus giving it color to make it visible. Moreover, proteins are made out of amino acids that are linked by a polypeptide bond (Campbell Biology 75). The purpose of this experiment was to determine whether an unknown class sample or food sample had any carbohydrates, lipids, or proteins in it. The expected result of the lab was that some substances would be present while other would be absent.
The weight of the final product was 0.979 grams. A nucleophile is an atom or molecule that wants to donate a pair of electrons. An electrophile is an atom or molecule that wants to accept a pair of electrons. In this reaction, the carboxylic acid (m-Toluic acid), is converted into an acyl chlorosulfite intermediate. The chlorosulfite intermediate reacts with a HCL. This yields an acid chloride (m-Toluyl chloride). Then diethylamine reacts with the acid chloride and this yields N,N-Diethyl-m-Toluamide.
The Phenol Red Carbohydrate Fermentation Broth test. This test is to determine the ability of microorganisms to ferment in a specific carbohydrate. If fermentation occurs, the pH level
The purpose of this experiment was to discover the specificity of the enzyme lactase to a spec...
The independent variable for this experiment is the enzyme concentration, and the range chosen is from 1% to 5% with the measurements of 1, 2, 4, and 5%. The dependant variable to be measured is the absorbance of the absorbance of the solution within a colorimeter, Equipments: Iodine solution: used to test for present of starch - Amylase solution - 1% starch solution - 1 pipette - 3 syringes - 8 test tubes – Stop clock - Water bath at 37oc - Distilled water- colorimeter Method: = == ==
An error that occurred in the experiment was during the ceric nitrate test because solution 4 should have produced a color change. During a base hydrolysis of aspartame, aspartic acid, phenylalanine and methanol are produced, therefore the ceric nitrate test should have been a positive for alcohol. A reason that this could have shown a negative result is because methanol is a volatile substance and it could have evaporated out, which would have caused a negative ceric nitrate test
Due to the nature of amino acids, a titration curve can be employed to identify
The mixture for that table’s flask was 15 mL Sucrose, 10 mL of RO water and 10 mL of Yeast, which the flask was then placed in an incubator at 37 degrees Celsius. In my hypothesis for comparison #4 the measurements would go up again with every 15 min. intervals because of the high tempeture and also be higher that then Controlled Table’s measurements. Hypothesis was right for the first part but was wrong for the second part of the comparison, the measurements did increase in the table’s personal flask but the measurements did not get higher than the Controlled Table’s measurements, see chart below. In conclusion, I feel that the substitution of glucose for sucrose made the enzymes work just as hard as the Controlled Table’s flask but just not as much because sucrose was too strong for the enzymes to
The Barfoed’s test for monosaccharides is used to differentiate between monosaccharides, disaccharides, and polysaccharides. Because of the acidity of the solution, only monosaccharides are able to reduce the copper ions. The solution will go from a sky blue to a red precipitate when there is a positive reaction for a monosaccharide. ("BIO 1510 Laboratory Manual,"
Therefore, the glucose concentration of solution X could have been anything between 1% and 10% glucose concentration. By its color, it seemed to be closer to test tube 1; therefore, I estimated it to be 7%. However, this method is extremely inefficient, and that estimate could easily be wrong. Hence, this method is semi-quantitative and has several limitations. Too much is left down to estimation, where human error could easily occur because in-betweens cannot be accurately measured and have to be guessed at.