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The aim of this investigation is to test for the different types of biological molecules found in different types of food

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Contents Page Introduction Page 2 Background Theory Page 3-4 Prediction Page 4 Materials and methods Page 5 Raw results Page 6 Analysis of results Page 6 Evaluation of materials and methods Page 6-7 Conclusion Page 7 References Page 8 Risk assessment sheet Page 9 Introduction The aim of this investigation is to test for the different types of biological molecules found in different types of food. We will be testing for starch, proteins, lipids and sugars. We will use nine (9) different types of food samples to test for all the above molecules in each food. When testing for different types of molecules in food, we use different types of food test. These tests are discussed below. To test for reducing sugars we will use the Benedict's test for Reducing Sugars (monosaccharides). Benedict's reagent is clear blue (from the presence of cupric copper ions, Cu++ ) but when combined and heated to boiling with a substance containing glucose in a chain form, the cupric ions are reduced to a cuprous form (Cu+ ) and then oxidized to form copper oxide (Cu2O). Copper oxide is a brownish-orange substance that is insoluble in water. Therefore, a positive reaction in a Benedict's test is the change of the clear light blue solution to an opaque orange-brown solution in a boiling water bath. This colour change indicates the presence of Glucose in a given solution. ...read more.


A benedict's test is then carried out which will be positive because the monomers are now free. Proteins Proteins are molecules, made up of amino acids. These amino acids contain carbon, oxygen, hydrogen and nitrogen. Sulphur is often present as well as iron and phosphorus. Each amino acid is made to the same design, with an amino group, a carboxyl group, a hydrogen atom, and a distinct R group (or side chain) all of which are bonded to an a-carbon atom. Amino acids are linked together in proteins by a peptide bond, made by the reaction of the carboxyl group of one amino acid with the amino group of the next. Polypeptides are just a string of amino acids, but they fold up and form the different structures of the proteins. The primary function of protein is to build body tissue and to synthesize enzymes. The biochemical test for proteins is the Biuret test. By adding some Biuret solution to a food sample; the presence of proteins would turn the food sample purple. Prediction I can predict that according to background knowledge that there will be some starch in the bread, sweet biscuit, the crisp and the cream crackers. The olive oil, nuts, the cream crackers and the crisp will also contain some lipids. It can also be predicted that the milk, eggs, nuts and cream crackers would contain some proteins. ...read more.


After the ethanol was added there was not an addition of water, the procedure for the emulsion test was not conducted the way it was meant to be. If this investigation were to be carried out again we would use a variety of foods such as meat, fish, different types of animal foods, this could help to compare the human diets and the animal diet. The results that would be obtained might be more or less the same, as all living organisms need the same nutrients, however might have different purposes in one's body. Time would also have to be an important factor. With enough time the experiments could be repeated and more accurate results would be taken. The method used could be used again however. The experiment would be repeated at least twice to obtained so reliable results; this will enable us to be aware of the mistakes in the procedures or recording of the results. Another way to improve this investigation could be to use raw materials not manufactured foods. If we used the ingredients contained in each food the results would be the same but it would help to explain and understand how certain foods contain certain nutrients. Conclusions It can be concluded that different kinds of food have different types of biological molecules and not all of them are the same. Eating different types of food which does not contain the same the biological molecules will provide the body with necessary nutrients. ...read more.

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