Preview

Identifying Biological Molecules with Colorimetric Chemical Tests

Powerful Essays
Open Document
Open Document
1319 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Identifying Biological Molecules with Colorimetric Chemical Tests
Identifying Biological Molecules with Colorimetric Chemical Tests

Objectives
Perform a series of accurate tests on biological molecules to detect the presence of carbohydrates and proteins, as well as the action of an enzyme on specific molecules.

Introduction
Unknown biological molecules can be correctly identified using various tests, including colorimetric chemical tests. Colorimetric tests are when a chemical reagent, such as Benedict’s, is used on a substance or solution and a certain color change occurs as a response. Carbohydrates and proteins, two of the larger types of biological molecules, also called macromolecules, are actually chains of molecules called polymers. The smaller molecules that build up these chains are called monomers. Proteins are chains of amino acid monomers. Enzymes are a type of protein that catalyzes or speeds up chemical reactions. The simplest and smallest carbohydrate is called a monosaccharide or simple sugar, and is a single monomer. Disaccharides are two monomers joined together and polysaccharides have three or more. Hydrolysis is a process that breaks down chains of polymers into monomers.
In this experiment, we Benedict’s reagent was used both before and after hydrolysis, to identify reducing sugars, which includes both monosaccharaides and disaccharides. Benedict’s reagent changes color in the presence of reducing sugars as well as heat. Low concentrations of sugar yield a yellow to orange color while higher concentrations will be red to brown. Lugol’s solution was used before and after hydrolysis to identify polysaccharides. Proteins were tested for using Biuret’s reagent, the alkaline chemical compound CuSO4. The action of enzymes on specific molecules was also determined, using the enzyme invertase followed by another test with Benedict’s reagent.

Materials/ Methods
Please see pages 47-52 in the Bio lab manual.

Results: In part 1 of this lab, we performed a series of tests on eight different

You May Also Find These Documents Helpful

  • Good Essays

    Carbohydrate – sugars, encompasses the monomers, called monosaccharides, small polymers called oligosaccharides, and large polymers called polysaccharides…

    • 712 Words
    • 3 Pages
    Good Essays
  • Good Essays

    Natural enzymes are proteins that catalyze biological reactions by lowering the activation energy of the reaction without being altered during the process. The enzyme used in this experiment was the β-galactosidase purified from E. coli. This enzyme hydrolyzes lactose and turns it into galactose and glucose. Since it is difficult to assay the activity of β-galactosidase, we will be using the artificial substrate, o-nitrophenyl-β-galactoside (ONPG) instead of lactose. ONPG is an analog of lactose and an advantage of using ONPG is that it is easy to determine the amount of ONPG cleaved by using spectrometric assay (1). The β-galactosidase hydrolyzes ONPG and yields a yellow solution that contains o-nitrophenol and galactose. The solution becomes more yellow as the more ONPG is being degraded. Using spectrophotometry, the absorbance of the solution can be determined at a wavelength of 420nm. The assays will help determine the Km, Vmax, and Kcat of the enzyme. In our assays, Na2CO3 is used to stop the reactions by changing the solution pH to basic and as a result the enzyme will become inactive.…

    • 463 Words
    • 2 Pages
    Good Essays
  • Satisfactory Essays

    5)a) Carbohydrates monomer(s) is monosaccharide’s which are simple sugars. The functional groups of carbohydrates are carbonyl and hydroxyl. The linkage type is a…

    • 1290 Words
    • 4 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Macromolecules Lab

    • 613 Words
    • 3 Pages

    A carbohydrate is an immediate form of energy in your body. Monomers is smaller than a polymer. For carbohydrate the monomer is sugar and the polymer is a polysaccharides. Carbohydrates are important to our body because we need to use energy. The purpose of this lab is to figure which one is the monomer and which one is the polymer.…

    • 613 Words
    • 3 Pages
    Satisfactory Essays
  • Powerful Essays

    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
  • Satisfactory Essays

    The starting molecules consist of the biological molecules with carbohydrates (monosaccharides) as the first choice. The order of use is given below.…

    • 668 Words
    • 3 Pages
    Satisfactory Essays
  • Powerful Essays

    Identifying macromolecules in the foods we eat is essential in comprising a healthy well-rounded diet ensuring our nutritional needs for cellular processes in the human body. The largest biological molecules are known as carbohydrates, lipids, and proteins. Carbohydrates are compounds of monosaccharides, disaccharides, and polysaccharides known as sugars and starches. Lipids, known as fats, are storage molecules in animals and plants. Proteins bind to other molecules performing key roles in DNA and RNA functions.…

    • 2217 Words
    • 9 Pages
    Powerful Essays
  • Good Essays

    PH lab report

    • 568 Words
    • 5 Pages

    After the LAB i had various different results for each indicator reaction to the unknowns.…

    • 568 Words
    • 5 Pages
    Good Essays
  • Better Essays

    Bio Lab Manuel

    • 36655 Words
    • 147 Pages

    of macromolecule is and how we can test for the presence of each in various solutions.…

    • 36655 Words
    • 147 Pages
    Better Essays
  • Better Essays

    To test the effect of a substrate concentration on enzyme activity, the amylase enzymes were combined with a different substrate concentration (starch) and the rate of the reaction was determined with the aid of I2kI. If starch was detected, the solution turned to dark blue; if the starch was already broken down, then reaction stayed colorless. To test the optimal PH, the starch and a buffer were combined at a specific PH level and the rate of reaction was tested. To determine the optimal temperature of amylase enzyme, the solution and amylases enzyme were held at various temperatures and the rate of reaction was determined.…

    • 2678 Words
    • 11 Pages
    Better Essays
  • Better Essays

    The term macromolecule is convenient because the bulk properties of a macromolecule differ from those of smaller molecules. These large chemical compounds have a high molecular weight consisting of a number of structural units linked together by covalent bonds, giving them a variety of structures and functions in the body. Macromolecules (also known as supermolecules) are commonly grouped into four major categories: proteins, nucleic acids, lipids and carbohydrates. These are mainly composed of polymers, long molecules made up of a large number of small, similar molecules, or monomers.…

    • 1148 Words
    • 5 Pages
    Better Essays
  • Good Essays

    A carbohydrate is an organic molecule containing only Carbon, Hydrogen and Oxygen with the general formula Cn(H20)n. They are made up of individual molecules called monomers which are joined together by condensation reactions to make a longer chain called a polymer. Carbohydrates are categorised in to three main groups; monosaccharides, disaccharides and polysaccharides.…

    • 757 Words
    • 4 Pages
    Good Essays
  • Good Essays

    functional groups (such as the bromine test for alkenes and alkynes), while other only a specific…

    • 1882 Words
    • 8 Pages
    Good Essays
  • Good Essays

    References: De Schweinitz, Jean. (2009). Chapter 7. Majors Biology Laboratory Manual, (81-88). Iowa. Kendall Hunt Publishing Company.…

    • 6827 Words
    • 28 Pages
    Good Essays
  • Powerful Essays

    Macromolecules also known as biological molecules are monomers which are the simple units of polymers. All macromolecules contain carbon and hydrogen which are found in organic compounds. In this Experiment we will test for the presence of protein, starch, lipids, and sugars by analyzing the content off food and / or other substances by utilizing different testing methods. In the scientific method, a chemical test that is sensitive to these groups can be used to identify molecules that are in that class. Testing involves many procedures that are very precise. This lab is broken down into five different sections; we will be using the Biuret Test for amino groups present in proteins. The Iodine Test to identify the presence of starch. The Grease Spot Test and the Sudan Dye test to identify the presence of lipids (fatty acids). The Benedict’s Test to identify the presence of reducing sugars.…

    • 2049 Words
    • 9 Pages
    Powerful Essays