Preview

Qualitative Analysis of Carbohydrates

Satisfactory Essays
Open Document
Open Document
367 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Qualitative Analysis of Carbohydrates
Lim, Jean Rya Que
2013 – 72199

ATQ 1 – Qualitative Analysis of Carbohydrates

Data Sheet:

A. Osazone Formation

Crystals Formed? (hot)
Crystals Formed? (Cold)
5% sucrose
Yes (orange)
Yes (yellow)
5% glucose
Yes (orange)
Yes (yellow)
5% fructose
Yes (brown)
Yes (brown)
5% maltose
Yes (orange)
Yes (gold)

B. Molisch Test

Color of Junction
Glucose
Purple
Sucrose
Purple
Starch
Purple

C. Bial’s Test

Color Change
Ribose
Yellow -> Dirty Green
Glucose
Yellow -> Dark Yellow

D. Seliwanoff’s Test

Observation
Sucrose
1st (Dark)
Glucose
2nd (Medium)
Fructose
3rd (Light)

E. Benedict’s Test

Color Change
Glucose
light blue -> Orange
Fructose
light blue -> light olive green
Maltose
light blue -> yellow brown
Sucrose
light blue -> blue green
Starch
light blue -> no change
Distilled Water light blue -> no change

F. Barford’s Test

Observation
Amount of Precipitate
Glucose
Blue Solution, Red Precipitate
Most
Fructose

Less
Maltose

More
Sucrose

Least

G. Hydrolysis of Polysaccharides
Total Drops: 11 (11 mins. )
Color Changes: Dark Violet -> Brown -> Orange -> Yellow

Unhydrolyzed - > Hydrolyzed
Hydrolyzed Starch
Blue -> brown
Hydrolyzed Sucrose
Blue -> reddish brown

Questions:

1) Draw the structures of the osazones produced in the experiment.

2) Theoretically, arrange the following sugars according to their reactivity with the Benedict’s Reagent (Glucose, Fructose, Maltose, Sucrose, Starch)
Glucose > Fructose > Maltose > Sucrose > Starch

3) What is the difference between the Benedict’s Test and Barfoed’s Test? The Benedict’s Test is used to test for the presence of reducing sugars (ie. Monosaccharides, disacchararides etc.) Meanwhile, Barfoed’s Test only tests positive for monosaccharides making it a more specific test for sugars.

4) Can Seliwanoff’s Test be used to differentiate sucrose from fructose? Why? Seliwanoff’s Test cannot be used to differentiate sucrose from fructose because Sucrose contains both the
Continue Reading
View Writing Issues

You May Also Find These Documents Helpful

  • Good Essays

    Carbohydrate Powders Case Study Answers
    • 1051 Words
    • 5 Pages

    Carbohydrate Powders Case Study Answers

    During an intense weight training workout, the glycogen stored in the muscles and liver is the main energy source. Optimal strength and endurance during your workouts it is very important that these glycogen supplies are completely restored before starting a new workout.…

    • 1051 Words
    • 5 Pages
    Good Essays
    Read More
  • Satisfactory Essays

    Bio 103 Lab Report
    • 649 Words
    • 3 Pages

    Bio 103 Lab Report

    3. Compare the Biuret test results of albumin and pepsin, the Benedicts, and starch results for potatoes and onions, and describe how one can determine the relative amounts of sugars present in a sample using the Benedicts test.…

    • 649 Words
    • 3 Pages
    Satisfactory Essays
    Read More
  • Satisfactory Essays

    General Biology: Critical Thinking Activity

    • 354 Words
    • 2 Pages

    General Biology: Critical Thinking Activity

    What does the Benedict’s reagent test detect? It is a test performed to test the reduction of sugars such as monosaccharide’s and disaccharides.…

    • 354 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Powerful Essays

    Pre-Lab: Identifying Carbohydrates
    • 1115 Words
    • 5 Pages

    Pre-Lab: Identifying Carbohydrates

    The point of this lab is to determine if a substance contains carbohydrates such as a reducing sugar and/or polysaccharides. This will be done by using Benedict’s reagent and Iodine stain tests. Benedict’s reagent will react to reducing substances in the solution by oxidizing it and changing the structure of the reducing sugar to form a colored precipitate. The color of this precipitate can be used to determine the concentration of reducing sugars in the substance. If the precipitate is blue no reducing sugars are in the substance. If the precipitate is bluish green, green, yellow, or orange it does contain reducing sugars. Iodine stain will be used to determine if the solution contains polysaccharides.…

    • 1115 Words
    • 5 Pages
    Powerful Essays
    Read More
  • Satisfactory Essays

    Review Sheet 39b
    • 603 Words
    • 3 Pages

    Review Sheet 39b

    We used a negative control to see if there is any amylase in the maltose…

    • 603 Words
    • 3 Pages
    Satisfactory Essays
    Read More
  • Satisfactory Essays

    Enzyme Lab: 1 And Add Lugol's Solution
    • 433 Words
    • 2 Pages

    Enzyme Lab: 1 And Add Lugol's Solution

    However, there were differences in the results of step 5/6 and step 3. In step 3, when Benedict’s reagent was added to the cracker there was no colour change. This indicated that there were no mono- or di- saccharides in the cracker. However, once the cracker was chewed in step 5, the amylase in the person’s saliva broke the polysaccharides into smaller groups (mono/di saccharides). Since the Benedict’s reagent indicates the presence of mono- and di- saccharides, there were prominent changes in the colour of the…

    • 433 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Satisfactory Essays

    Macromolecules: Glucose and Lab Manual Pg.
    • 392 Words
    • 2 Pages

    Macromolecules: Glucose and Lab Manual Pg.

    The purpose of this lab is to determine the presence of glucose, starch, and protein in various samples through standard tests.…

    • 392 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Good Essays

    Lab 2 Bio 100
    • 525 Words
    • 3 Pages

    Lab 2 Bio 100

    List whether each of the following substances was positive or negative for reducing sugar, as indicated by the Benedict's test. (6 points)…

    • 525 Words
    • 3 Pages
    Good Essays
    Read More
  • Good Essays

    health information management
    • 1233 Words
    • 11 Pages

    health information management

    1. Benedict’s solution is added to white grape juice and heated. The color changes from blue to orange. Based on this result, what biological molecules are present in the white grape juice?…

    • 1233 Words
    • 11 Pages
    Good Essays
    Read More
  • Good Essays

    Carbohydrate Counting Essay
    • 452 Words
    • 2 Pages

    Carbohydrate Counting Essay

    If you take at least three or four doses of insulin a day or use an in-…

    • 452 Words
    • 2 Pages
    Good Essays
    Read More
  • Good Essays

    Four Major Biological Macromolecules
    • 1411 Words
    • 6 Pages

    Four Major Biological Macromolecules

    Firstly, a source of error may occur during the Benedict 's test. Positive results may occur when their should not be. This is due to the fact that there may be a presence of another substance that can be oxidized other than reducing sugars. Furthermore, another source of error may be the dirty test tubes which may sway some reactions when solutions are mixed. Measurements may be another source of error. Such as using a plastic measuring cup can measure off by +/- 5%, and estimating the amount of solution in half a pipette. To improve this lab, and the Benedict test, another test should be done for non-reducing sugars that may give positive results. Another way to improve the lab is to use distilled water as a solution for comparision. The distilled water will not result in a positive control in the test due to the fact that water does not contain any macromolecules. The water can be compared with other solutions for a negative control. The results for iodine test indicate that solutions 1,2,3,4,5,6,9,10 and 11 turn yellow when mixed with iodine and therefore the solutions do not contain starch or glycogen. The yellow is a result from a colorless solution mixed with iodine. Solutions 7 and 12 turned red/brown when iodine was added. Conclusions can be made that these solutions contain glycogen. The highly branched structure reacting with iodine and gives it that red/brown color. Furthermore, solution 8 turned blue/purple which is an indication that it is starch, and it was also expected to result positive because it was 1% starch solution. Solution 7 therefore contains amylose and amyloepectin. But it is the amylose that initially reacts with iodine creating a blue color. Secondly, the results for the Benedicts test showed that solutions 2, 5, 7, 8, 9, 11 and 12 had a negative control. No color change. Therefore these solutions do not contain any molecules that can reduce cupic ions such as a reducing sugar. An…

    • 1411 Words
    • 6 Pages
    Good Essays
    Read More
  • Good Essays

    Biological Molecules Lab Report
    • 853 Words
    • 4 Pages

    Biological Molecules Lab Report

    The Benedict’s test is to test for reducing sugars, Iodine test is to test for starch, and Biuret test, is to tests for proteins. We came to a conclusion that biuret solution is a blue liquid that changes to purple when proteins are present and to pink in the presence of short chains of polypeptides. The violet color is a positive reaction in a Biuret test. Proteins give a strong biuret reaction because they contain a large number of peptide bonds for example milk. For part 2 of this lab we are trying to identify carbohydrates and we got to a result that Benedict solution is used to test for simple carbohydrates. Benedict's solution is a blue colored liquid that contains copper ions and when Benedict's solution and simple carbohydrates are heated, the solution changes to orange and red for example Dextrose. As we all know from experience, lipids leave translucent spots on unglazed brown paper bags and the reason lipids make a translucent mark on brown paper is because their small particles fill up the spaces in the paper and based on this observation a translucent spot is visible, then the presence of lipid has been…

    • 853 Words
    • 4 Pages
    Good Essays
    Read More
  • Satisfactory Essays

    Testing for Macromolecules
    • 466 Words
    • 2 Pages

    Testing for Macromolecules

    The positive test for glucose is be adding Benedict’s solution. In the experiment, the glucose solution had the most dramatic reaction with the Benedict’s solution after it got heated. It turned to an opaque yellowish orange solution with dark-orange precipitate at the bottom while other samples all turned to a colour related to blue, other than the unknown solution.…

    • 466 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Satisfactory Essays

    Nutritional Analysis
    • 407 Words
    • 2 Pages

    Nutritional Analysis

    1) After analyzing my diet I have found that I do meet certain nutritional guidelines. The areas in which I take in an adequate or near adequate amount of nutrients are: Milk, Grain, Energy (kcals), Protein, Fiber, Sodium, and Thiamin. I drink a sufficient amount of water due to the demand of my physical activities and this is probably why I make sure I have a sufficient Protein intake also.…

    • 407 Words
    • 2 Pages
    Satisfactory Essays
    Read More
  • Satisfactory Essays

    Chemistry Lab Questions
    • 941 Words
    • 4 Pages

    Chemistry Lab Questions

    2. List whether each of the following substances was positive or negative for reducing sugar, as indicated by the Benedict's test. (6 points)…

    • 941 Words
    • 4 Pages
    Satisfactory Essays
    Read More

Related Topics