Polymers Essay Example | Topics and Well Written Essays - 1000 words

Polymers - Essay Example Glycogen also is used for long term energy energy storage, but only animals. Animals can hydrolyze this polymer to obtain glucose. Starch and glycogen have many hydrogen and oxygen rich functional groups which make them reactive with water, during the hydration and condensation processes which created and store energy within the body. Cellulose has a different king of bond between monomers, forming linear polymers that are cross-linked by hydrogen bonds with other linear chains. Cellulose is the principal structural molecule in the cell walls of plants and algae. Animals cannot hydrolyze this polymer to obtain glucose without the help of intestinal bacteria, it is referred to as fiber. Another characteristic of monosaccharides is that they can act as mild reducing agents. This is because the aldehydo group that is present can be oxidized to form a carboxylic acid group, or in the presence of a base, a carboxylate ion group. Fructose can also act as a reducing sugar, even though it has a ketone group instead of an aldehyde group. Under basic conditions, the fructose molecules can, essentially, have the location of the carbonyl bond switched to convert them into a glucose molecule. This occurs in a number of steps involving removing hydrogens from the #1-C and its oxygen and moving them to the #2-C and its oxygen. Glucose is heated with Benedict's reagent (CuSO4, NaOH, a... Glucose is heated with Benedict's reagent (CuSO4, NaOH, and tartaric acid) to form a brick red precipitate. Sucrose does not react under these conditions. Fructose does form a red precipitate with Benedict's reagent. Carbohydrates that contain aldehydes or a-hydroxymethyl ketones can be oxidized by Cu(II) ion and are classified as reducing sugars. They reduce the Cu(II) ion to Cu(I). - Relate the behaviour of the amino acids / proteins under test to their structural characteristics. Biuret Test for Proteins: Biuret reagent is a light blue solution which turns purple when mixed with a solution containing protein. The purple color is formed when copper ions in the biuret reagent react with the peptide bonds of the polypeptide chains to form a complex. Because amino acids contain a free amino group, they are readily detected with ninhydrin reagent which reacts with free amino groups to form a purple or violet colored substance. Ninhydrin reagent can also be used to detect proteins, but the proteins must be heated or digested to hydrolyze the protein into free amino acids. - Relate the behaviour of the lipids under test to their structural characteristics. In lipids carbon and hydrogen predominate because there is very little oxygen which makes them more of less hydrophobic. Diverse types of lipids have different roles including energy storage and structural and metabolic functions. Fats are polymers of fatty acids (usually three) and one glycerol molecule, formed by dehydration reactions, and are called triglycerides or triacylglycerided. Fats are tremendous sources of energy and can store approximately 2 times better than polysaccharides. Saturated fatty acids have no double bonds between carbons, and