Iodine And Benedict Lab Experiment

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INTRODUCTION: In this lab, proper laboratory technique was implemented to have the experience in the lab. Furthermore, the unknown solution needed to be investigated, to determine the solution’s macromolecules. Three methods were comprised to determine the unknown but a set of other solution were used to help as indicators to match the unknown solution’s results. It consisted of biuret, iodine and benedict solution. Iodine solution is used to determine if the source had starch or glycogen. If the source had glycogen consisted inside, there would be a reddish-brown precipitation occurring (Daniel Luzon Morris,1946). Iodine can also react with the starch which could potentially create a The colour of the precipitate that forms a purple precipitate …show more content…
During the benedict test, solution 9,10 and 12 tested positive. Finally, for biuret, only solution 9 was positive.
In order to determine the negative charge of this experiment, a solution had to remain neutral in all three test or at least not react. Distilled water (solution 11) was deemed as negative indicator as it would not result in any changes. Whether, it was in biuret, iodine or benedict, it would result in as a negative indicator. Anything that deviates from the comparison of distilled water would be considered as positive control.
The glucose solution did not change colour but remained yellow during the iodine test. Therefore, there is no glycogen or starch. When the benedict test occurred, the colour shifted from green to brown within minutes. Later the orange would turn into a very rose red. Glucose is supposed to be a red precipitate when detected by the benedict solution. (B.K Sur, R.K. Shukla, and V.S Agashe, 1972) It revealed that there was a presences of sugar in the solution which caused the sugar to change the solution colour as aldose was causing a positive reaction. During the biuret test, the glucose did not change any colour because there was no sign of any protein residing inside the
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It was tested as a negative because there was no glycogen or starch to be found. Although, sucrose was a basic sugar, there was no reduced sugar to be found which resulted in a negative for the benedict test. This could have potentially as we recorded the solution wrong or a contamination occurred during the testing. Perhaps if we ran a second trial for the solution, we could potentially see a result for this solution. Next, the sucrose tested negative in the biuret test as there is no protein in the

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