Top-Rated Free Essay
Preview

Lab 2 Proteins and Starches

Satisfactory Essays
419 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Lab 2 Proteins and Starches
Daniel Bergey

Lab 2: Proteins and Starches

Purpose
The purpose of lab 2 and both tests with proteins and starches is to determine which substance contains either protein or starch.

Hypothesis
Proteins: I predict that any substance I test that derives from a living organism is will test positive proteins. Any substance that isn’t from a living organism more than likely will test negative for proteins.

Starches: I predict that any substance that contains any level of glucose will test positive for starch.

Materials
Physical: None

Virtual:
1. Test Tube Rack
2. 4-5 Test Tubes
3. Transfer Pipet
4. Protective Glasses
5. 3 Pieces of Paper Bag
6. DiWater
7. Evaporated Milk
8. 50% Egg White Solution
9. 1% Sucrose Solution
10. 1% Starch Solution
11. Onion Juice
12. 10% Sucrose Solution
13. Vegetable Oil
14. Biuret Reagent
15. Iodine
16. Benedicts Reagent

Methods
In this lab there are I complete two different tests. The procedure was relatively the same for each test. I would first add 3ml of a given substance to a test tube, followed by 5 drops of either Biuret Reagent or Iodine. Once the agent is added, I swirled the two substances and then observed the results. The first was to test proteins, and the second, was to test starches.

In the first test, Proteins, I used biuret reagent to determine which of the substances had protein. The substances I added biuret reagent to were, diwater, egg white solution, milk solution, and 1% sucrose solution. The procedures in which I took are the same ones listed above, using the biuret reagent.

In the second test, Starches, I used Iodine to determine which substance was starch and which wasn’t. The substances I added iodine to were, diwater, 1% starch solution, onion juice, and 1% sucrose solution. The procedures in which I took for the second test were the same ones as list in the first paragraph, using iodine.

Results
DiWater
Blue
50% Egg White Solution
Purple
Evaporated Milk
Purple
1% Sucrose Solution
Blue

Test 1: Proteins
Contents Results

Test 1: Starches
Contents Results
DiWater
Yellow
1% Starch Solution
Purple
Onion Juice
Yellow
1% Sucrose Solution
Yellow

Conclusion

Proteins:

Starches:

In both tests with the various substances my hypothesis was proven to be correct. I can conclude that if a substance derives from a living organism, it is more than likely to test positive for protein. While if a substance contains any level of glucose, in is more than likely to test positive as a starch.

You May Also Find These Documents Helpful

  • Good Essays

    A few experiments were performed to test for the presence of the different types of macromolecules of various solutions. The iodine tested for starch and glycogen, Benedict’s test tested for reducing sugars for carbohydrates and biuret test was performed to test for proteins. It is necessary to understand how important controls are in a lab experiment. A control is where all of the experimental variables can be controlled and monitored. Results are determined by comparing these variables to the control. Without them, no results would be valid in the experiment. To tell whether or not the experimental procedure were carried out properly and correctly, treatment controls were used. They can either be positive or negative. Correct data with followed procedures, resulting in a working experiment would be a positive control. On the opposite hand, negative controls would give negative results if everything were to be followed in the experiment.…

    • 1158 Words
    • 5 Pages
    Good Essays
  • Satisfactory Essays

    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
  • Better Essays

    Macromoleules of Life

    • 1662 Words
    • 7 Pages

    In my first experiment to test for proteins the egg white with the Bluret reagent should come out positive for being a protein. The pepsin in the Bluret reagent should be positive and should be a protein. The test for sugar in the Bluret reagent should be negative and I don't think it is a protein. The test with the distilled water with the Bluret reagent should be negative and is not a protein. In the second experiment to test for glucose with the Benedict reagent sugar should be positive for glucose. Starch mixed with the Benedict reagent is probably positive for glucose because it is a polysaccharide. Onion juice mixed with Benedict reagent is probably positive for glucose because it is a fructose. Distilled water with Benedict reagent should be negative for glucose. The third experiment to test for starch using with and without the IKI reagent by looking under a microscope a slice of potato cells should have several shapes to it and with the IKI reagent should look have more of a stronger shapes and color to it. The onion cells should have a more stringy look to it and with the IKI more color. The fourth experiment is testing for lipids using the Sudan III on a potato, onion, oil and dH2O. I believe the oil will determine it is a lipid. The fifth experiment the chemical bonding of mixing an egg yolk, vegetable oil and vinegar should make mayonnaise as long as you continually mix a good amount of vegetable oil…

    • 1662 Words
    • 7 Pages
    Better Essays
  • Good Essays

    Macromolecules of Life

    • 671 Words
    • 4 Pages

    Using IKI reagent to test the detection of starch in an onion and a potato. This is done by adding a drop of IKI reagent to the potato and the onion and examining both of them under a microscope looking for cell presence.…

    • 671 Words
    • 4 Pages
    Good Essays
  • Better Essays

    Oxidation of Alcohol

    • 1599 Words
    • 8 Pages

    contains glucose or sucrose. Benedict 's test is a way to determine the presence of aldehydes in a…

    • 1599 Words
    • 8 Pages
    Better Essays
  • Satisfactory Essays

    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
  • Good Essays

    b. Benedict's Test: monosaccharide + Benedict's solution (light blue)  green to red depending on concentration of sugars…

    • 3277 Words
    • 15 Pages
    Good Essays
  • Good Essays

    Organic Molecules

    • 1537 Words
    • 7 Pages

    Hypothesis: If the carbohydrate contains available ketone or aldehyde molecules then they are reducing sugars.…

    • 1537 Words
    • 7 Pages
    Good Essays
  • Good Essays

    10. To test for proteins, fill each test tube with 5ml of the substance indicated by the label. Add 5 drops of Biuret reagent to…

    • 740 Words
    • 3 Pages
    Good Essays
  • Powerful Essays

    Materials: 14 test tubes, 1 test tube rack, 1 paper towel, 5 ml Benedicts solution, .5 ml Iodine solution, 2 ml Biuret reagent, hot plate, samples 1-5, A, and B. Procedure: Obtain materials, Label the test tubes 1-5 ad A and B…

    • 897 Words
    • 4 Pages
    Powerful Essays
  • Better Essays

    Protein Synthesis Lab

    • 958 Words
    • 4 Pages

    The purpose of this lab was to learn about the Biuret assay reaction to determine if it can detect proteins and amino acids; also, to understand the process of “salting out” proteins and how to determine the amount of protein in a solution. In order to do so, egg white and ammonium sulfate were mixed on ice and then put into the centrifuge. After PBS was added, the amount of protein could then be determined. After that, 14 test tubes were used to create a set of protein standards. Biuret solution was added to all 22 tubes and vortexed. Absorbance data was then collected by these protein standards using the SpectroVis Plus, and there was a direct relationship between absorbance…

    • 958 Words
    • 4 Pages
    Better Essays
  • Good Essays

    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
  • Good Essays

    There are four main macromolecules; proteins, nucleic acids, lipids, and carbohydrates. The presence of some of these, such as sugar, fat, starch, and protein, can be determined using tests such as Benedict’s solution, Lugol’s iodine solution, Biuret’s reagent, and Sudan III. Control tests were performed to determine what a positive result would appear like. Then the tests were performed using substances containing sprite, fries, hamburgers, and chicken nuggets. Results matching the control results would establish how much protein, fat, starch, and sugar there was in each mixture.…

    • 2229 Words
    • 9 Pages
    Good Essays
  • Satisfactory Essays

    Does the amount of time that orange juice is swished in a human mouth affect the pH of the saliva, which could inhibit the digestion of the starches in the orange juice?…

    • 556 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    Molisch Test Lab Report

    • 419 Words
    • 2 Pages

    In this experiment, all the test solutions show a positive test with Molisch reagent and concentrated sulfuric acid to form a violet ring at the interface of two layers. This is because the samples used in this experiment are maltose, glucose and starch which are considered as carbohydrate that should give a positive reaction. Monosaccharides give a rapid positive test compare to disaccharides and polysaccharides which will react slower. Therefore, the…

    • 419 Words
    • 2 Pages
    Good Essays