Lab Report Free Amino Acid

The protein molecules in many foods provide the amino acid building blocks required by our own cells to produce new proteins. To determine whether a sample contains protein, a reagent called Biuret solution is used. Biuret solution contains copper ions. However, the chemical state of the copper ions in Biuret solution causes them to form a chemical complex with the peptide bonds between amino acids (when present), changing the color of the solution. Biuret solution is normally blue, but changes to pink when short peptides are present and to violet when long polypeptides are present.

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

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

The purpose of this lab was to test different substances using various procedures to see what biomolecules were present and ultimately find out what restaurant Anna Lyza had eaten at before she died. For the first control test, we used vegetable oil to test for lipids. So, if the solution does not contain lipids, it does not become translucent when placed onto a paper bag square and held up to a light. So, it is a negative result. However, in the presence of lipids, the solution will become translucent when placed onto a paper bag square and held up to a light. Therefore in this case, the result is positive. On the other hand, we used albumin egg to test for proteins in another control test. If the solution does not contain proteins, it will not experience any color change and so it is a negative result. When there are proteins existing in the solution, it will turn bluish/purplish and for this reason it is a positive result. Furthermore in the third control test, we used dextrose to test for simple carbohydrates such as glucose. If the solution does not contain simple carbohydrates, it will not undergo any color change and will remain a blue color. So, it is a negative result in this circumstance. If there are simple carbohydrates present in the solution, the solution will turn reddish and so the result is positive. For the last control test, we used starch solution to test

This Lab Report is an analysis of the results of a two-part experiment. In the first part, we used a gel filtration column to separate the components of a mixture composed of protein and non-protein molecules. By doing so we hoped to obtain fractions that contained single components of the mixture, while also gaining insight into the relative molecular weight of each component compared to each other. We would then plot these fractions onto nitrocellulose paper in order to determine which fractions had protein. In the second part, we would use the fractions which we had determined had protein to conduct an SDS-PAGE. By doing so we hoped to determine an estimate on the molecular weight of the proteins present in each fraction by comparing it to a tracker dye composed of a variety of molecules of differing molecular weight.

Create a control group by testing the three reagents in distilled water. Fill three tubes one centimeter of the length with distilled water. With a permanent marker, label the test tubes according to which reagent will be used. In order to test for sugars, preheat a beaker that is three-fourths full of tap water and bring the water to a boil. In the first test tube, drop five drops of biuret reagent to test for protein, in the second, drop five drops of iodine to test for starches, and in the third, drop five drops of Benedict’s reagent to test for sugars. Using a tube grabber, place only Benedict’s reagent test tube in the boiling water for a total time of three minutes. Using the tube grabber, carefully remove the Benedict’s reagent tube from the boiling water and record the color of all 3 liquids in the test tubes. Place the tubes in the

In doing the lab, one was able to determine the characteristics of the given solutions, containing different macromolecules, whilst doing the multiple tests. The tests performed were,

A cell, the building block of all living organisms, is composed of four fundamental biomolecules: proteins, carbohydrates, sugars and lipids. Proteins provide a vast amount of functions cells such as they serve as enzymes, provide structural support to cells, and act as antibodies. Reagents are used to spark a chemical reaction. The reagent used to detect protein traces in a substance is Biuret’s. Biuret’s will turn purple if proteins are present and blue if they are none. Biuret’s copper particles, have a charge of +2, are diminished to a charge of +1 when peptide bonds, which are in proteins, are present, creating the color change. Polysaccharides, which are carbohydrates, are most notably known to provide energy to the body, but they also help in breaking down fatty acids. Iodine is the reagent used to determine whether a substance has starch in it. The iodine/starch complex has energy levels that are only for retaining unmistakable light, giving the complex its extraordinarily dark black-blue shade. If there is no starch found, iodine will remain its natural yellowish-brownish color, but if starch is present, iodine will turn blue-black. Monosaccharides, which are sugars, like polysaccharides, provide the body with energy. To detect monosaccharides, the reagent, Benedict’s, is used. Benedict’s reagent is added to a test tube, then it is placed in

Box on right illustrates the peptide bond resulting from the condensation of both the amino acids. The box on the left illustrates the separation of the hydroxide group from glycine and the hydrogen atom from valine.

Proteins are complex structures made up of chains of amino acids. Each protein has a different function such as enzymes to catalyze reactions or protein hormones to trigger certain functions of a cell. First let’s start with the most basic component of a protein: an amino acid. An amino acid is made up of a central carbon atom attached to a hydrogen atom, a carboxyl group, an amino group, and an R group which varies

The amino acids bond together in bonds called peptide bonds. A chain of amino acids is called a polypeptide chain. The structure in which the amino acids are bonded determines the function of the protein. There are about twenty different amino acids, but there is a wide variety of possible combinations that amino acids can bond, therefore proteins have quite a lot of functions. Some things proteins are used for are the building of the muscles, tendons, organs, glands, nails, and hair. There are many more different functions for proteins. To detect proteins in test materials, there is an identifying agent called Biuret Solution which when mixed with the test material. It turns purple if it contains a protein. The darker the violet color, the more concentrated it is with protein.

The he investigated an organic compound of dinitrochlorobenzene, this encouragingly stained the amino acids bright yellow and making them stand out in a clear band when subjected to partition

We tested water each time due to needing a solution to compare each tube to. When Benedict’s Reagent was added to unknown #2 and then boiled, the substance turned yellow indicating that a reducing sugar was present. After adding Lugol’s reagent to the unknown #2 there was no change in color, therefore the presenting the absence of polysaccharides. After adding Biuret reagent to the unknown #2 substance, the substance turned a light purple color; indicating the presence of protein in the unknown solution. Lastly, after adding the Sudan solution to the unknown #2 substance a pink mixed solution was present in the tube.

Campbell and Farrell define proteins as polymers of amino acids that have been covalently joined through peptide bonds to form amino acid chains (61). A short amino acid chain comprising of thirty amino acids forms a peptide, and a longer chain of amino acids forms a polypeptide or a protein. Each of the amino acids making up a protein, has a fundamental design that comprises of a central carbon or alpha carbon that is bonded to a hydrogen element, an amino grouping, a carboxyl grouping, and a unique side chain or the R-group (Campbell and Farrell 61).

B) Proteins Proteins are made up of chains of amino acids. Each protein folds into a characteristic three dimensional shape that is essential to its function. They perform a variety of functions in cells and are probably the most diverse macromolecule in living systems. The Biuret test detects the presence of proteins and short peptides (short chains of amino acids). Biuret reagent contains a strong solution of sodium hydroxide (NaOH) and a very small amount of dilute copper sulfate solution. The reagent changes color in the presence of a protein because the amino groups in the amino acids react with the copper ions producing a violet color. A negative result is blue.