By finishing lab exercising 6: Biologically Important Molecules. we are able to execute trials such as the Benedicts Test for Reducing Sugars. Iodine Test. Biuret Test. Sudan IV Test. and in conclusion the Grease-Spot Test that detect the presence of biologically of import saccharides. protein lipoids and nucleic acids. Most known compounds in life being are if fact saccharides. lipoids. proteins. and nucleic acids. Each of these supermolecules are tested otherwise. The Benedicts trial identifies cut downing sugars based on their ability to cut down cuprous ions to cupric oxide at basic pH ensuing in a green to reddish orange colour. The footing for the iodine trial for amylum is since amylum is a coiled polymer of glucose. the iodine interacts with the coiled molecules turning blue black. The Biuret trial. trials for proteins by look intoing if there are the presence of long concatenation polypeptides. in making so do a colour alteration of violet. The Sudan IV trial for lipoids is based the it lipids ability to absorb pigment such as the Sudan IV
Materials and Methods:
Obtain seven labeled trial tubing. and add each stuff being tested to its ain trial tubing. Then add 2mL of benedict solution to each tubing and topographic point the trial tubing in a gently boiling H2O bath for 3 proceedingss. observe any colour alteration if any at all. After the 3 proceedingss remove the trial tubing go forthing them to chill to room temperature. so record observations in table 6. 1. Iodine Trial
Obtain seven labeled trial tubing adding stuffs that are being tested to their ain specific trial tubing. Add six beads of I to each tubing record any colour alterations in table 6. 1. Biuret Test
Obtain five labeled trial tubing adding the stuffs being tested to the trial tubing. so add 2mLof 2. 5 % Na Hydroxide to each trial tubing. Record any colour alteration in table 6. 2. Solubility of Lipids in Polar and Nonpolar Solvents
Obtain two trial tubings. In one tubing add 5 milliliter of H2O and to the other add 5 milliliter of propanone. Then add a few beads of vegetable oil to each tubing and record observation. Sudan IV Test
Obtain five labeled trial tubing adding stuffs to each trial tubing. Add five beads of H2O to prove tubing one and five beads of Sudan IV to the staying trial tubings. Record colour alterations in table 6. 3.
Obtain a piece of brown wrapping paper and utilizing an oculus dropper add a bead or salad oil. H2O. honey. murphy juice and onion juice to different corner near a different corner of the paper. Let the fluids to vaporize so keep the paper up to visible radiation and compose down any observations about each topographic point in table 6. 4.
In the Benedicts test we tested different solutions for cut downing sugars. While one solutions changed colour to green or a ruddy brown colour. others did non. Since the Onion juice. glucose solution and the reduction sugar solution changed colour to either green or dark ruddy colour. this is proof that the solutions where able to alter cuprous ions into cupric oxide. The other solutions such as the H2O murphy juice and so on did non respond to the Benedict’s reagent intending they did non hold free aldehydes or ketones with their solutions.
In the Iodine trial for amylum. lonely two of the substance reacted with the I. The murphy juice and the starch solution bend to a dark blackish colour when the I was added shows that there are coiled saccharides that are with the juice and starch solution. As for the solutions and substance that did non respond with the I that does non intend that there are non saccharides with in the solutions merely that the saccharides are non in a coiled construction. since I will non respond with saccharides unless they are coiled polymers.
In the Biuret trial. we tested several solutions for protein and merely two solution came up as a positive reaction. The egg albumins and the amino acerb solutions had a violet colour alteration significance there was the presence of at least one long concatenation polypeptide doing thelor alteration and a positive reaction for both trial substances. Other solution such the protein solution did non ensue in a positive reaction because it is possible that there merely single amino acids cause in non to give a positive reaction.
In the solubility of lipoids in polar and non-polar dissolvers the consequences where to be expected which the H2O and the vegetable oil. After adding the vegetable oil into the trial tubing incorporating H2O the oil did non blend. it stayed on top of the H2O and together. In the propanone after the vegetable oil was added the propanone became cloud. This shows that lipoids are soluble in propanone ( a non-polar substance ) and non in H2O ( a polar substance ) .
In the Sudan IV trial for Lipids. four solutions where tested. one which gave a positive reaction. The vegetable oil and the Sudan IV solution gave a positive reacting since the ruddy pigment of the Sudan IV was absorbed in the vegetable oil. As for the other solutions it is possible that they contain lipid but did non give a clear reaction to whether or non they do as in the reaction with the vegetable oil. The H2O and Sudan IV solution changed colour because they merely mixed in or the H2O could hold non been 100 % clean. In the Grease-spot the trial. we applied several different nutrient merchandise solutions to a piece of brown paper leting it to dry. The intent of this was to see which solution contained lipoids by seeing if they left a semitransparent lubricating oil grade. All the substances produced a lubricating oil grade except the H2O. The lubricating oil grade of the other four solutions all looked the similar while the grade that was left by the H2O was dry but merely wrinkled and no lubricating oil grade.
Vodopich. Darrell S. . and Randy Moore. “Biologically Important Molecules. ” Biology Laboratory Manual. New York: McGraw-Hill. 2014. 57-70. Print. Mason. Kenneth A. . Jonathan B. Losos. Susan R. Singer. Peter H. Raven. and George B. Johnson. Biology. N. p. : n. p. . n. d. Print.