Protiens

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Laboratory Report
Section 3.1-Test for Proteins
A protein is a long chain of amino acids that are linked from end to end by peptide bonds. The function and shape of the protein are determined by the sequence of its twenty amino acids. Proteins perform different functions in a cell. For example, regulatory proteins regulate, or control, cellular metabolism. Hemoglobin carries oxygen and carbon dioxide through the red blood cells of vertebrates and through the plasma of invertebrates, and transport proteins simply move substances from one region of the body to the next. Enzymes are also proteins that are capable of speeding up specific chemical reactions. In this experiment, we are testing for the presence of proteins, or either peptides. The Biuret test was used in this experiment, because the reagent will change color in the presence of proteins or peptides. In the presence of proteins, the reagent will turn purple, and if there are peptides, the reagent will turn pinkish-purple. The hypothesis is in fact that a protein can contain one or more polypeptide chains, which are very long chains of amino acids.
In this particular experiment some of the equipment used is a millimeter ruler, a wax pencil, and four clean test tubes. The presence pf proteins or peptides will be tested in the following solutions: distilled water, albumin, pepsin, and starch. Now envision that you are an observer of this experiment. The first thing that you see is the experimenter, whom will label the four test tubes at two different measurements. The first mark is made with the wax pencil at the 2 cm line, and the second mark is placed at the 4 cm line. (These measurements are marked accurately when the millimeter ruler is places on a flat surface and the glass test tube is placed on top of it.) The test tubes are also labeled one through four, so that you are able to keep up with each solution and its results. The four test tubes are placed ...