Protein Structure Essay

2349 Words 10 Pages
Introduction:
A human has thousands and thousands of different proteins, each with a specific structure and function. Along with their diverse functions, they vary in structure, each protein having its own unique three-dimensional shape. Proteins are polymers of amino acids joined together by peptide bonds. There are 20 different amino acids to make up all the different proteins on the earth. Each of the amino acids is composed of a central carbon bonded to a hydrogen, a carboxyl group, an amino acid group, and an R-group (Bowen, 2002). The R-group is what distinguishes one amino acid from another. All proteins share three levels of structure, known as primary, secondary, and tertiary structure. A fourth level, quaternary structure, exists
…show more content…
59). The primary structures are the proteins sequence of amino acids. The amino acids are arranged in a linear arrangement. The secondary structures are the areas of coiling or folding within a protein. The coils or folds are results of hydrogen bonds between the repeating constituents of the polypeptide backbone. Two main types of secondary structure include the α helix, a coil held together by hydrogen bonding between every fourth amino acid and the β pleated sheet, two or more segments of the polypeptide chain lying side by side are connected by hydrogen bonds between parts of the two parallel segments of polypeptide backbone. The tertiary structure is the overall shape of a polypeptide resulting from interactions between the R-groups. Each unique shape of each protein gives it a specific function. The different structures are what mainly affects the protein’s shape. However, the protein’s structure also depends on the protein’s environment. If the pH, salt concentration, temperature, etc. is altered, the weak chemical bonds and interactions within protein may be destroyed, causing the protein to unravel and lose its shape (Urry, Cain , Wasserman, Minorsky, …show more content…
The first tube was set up with 8 mL of starch, 1 mL of pH 7, 0 mL of salt, and 6 mL of water. The second tube was set up with 8 mL of starch, 1 mL of pH 7, 3 mL of salt, and 3 mL of water. The third tube was set up with 8 mL of starch, 1 mL of pH 7, 6 mL of salt, and 0 mL of water. The fourth tube, the control, was set up with 8 mL of starch, 1 mL of pH 7, 0 mL of salt, and 6 mL of water. There were 7 additional tubes for each of the four different solutions, total of 28 tubes, each set up with 3 drops of potassium iodide and 2 mL of water. One mL of each four solutions was added separately to one of the additional tubes instantly to account for time zero. Right after, 1 mL of the enzyme was added to each of the three original solutions to begin the reaction, and none to the fourth. At three minute intervals, 1 mL of the reaction mix is removed and added to another fresh tube that was set up with 3 drops of potassium iodide and 2 mL of water. Each 3-minute interval, 1 mL from each tube is transferred into cuvette. Using a spectrophotometer set to 605 nM, the absorbance was measured of each of the samples collected. The results were then

Related Documents