Deoxyribose Lab

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Abstract In this experiment, the isolation, characterization, and determination of concentration and purity of deoxyribonucleic acid or DNA from Allium Cepa or onion was performed. DNA was isolated through the use of a homogenizing solution. The absorbance ratio was 1.5, which indicates protein contamination. Moreover, the characterization of its components was conducted through the use of different chemical tests. The DNA gathered by the group bore positive results only on Test for Deoxyribose; compared to the standard solution, which bore positive results on all chemical tests, namely, Test for Deoxyribose, Test for Phosphate, Test for Purines, and test for Pyrimidines.

Introduction Nucleic Acid is one of the essential biochemical molecules
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The reagents used were Diphenylamine reagent which contains concentrated H2SO4. The standard solution used for this test is the deoxyribose standard solution. In the sample, only a faint blue solution appeared, which indicates a small presence of deoxyribose. In test for Phosphate, the standard solution was the Phosphate solution and the reagents used were concentrated H2SO4, concentrated HNO3, 2.5% ammonium molybdate solution. The principle involved in this test is the precipitation of phosphate which bores a yellow-colored solution and yellow precipitate. In the sample, neither a yellow-colored solution nor a yellow precipitate appeared which indicates the absence of phosphate in the sample. In the test for Purines, or Murexide test, the standard solution used was solid guanine. The reagents used were concentrated HNO3 and 10% KOH. Positive results should be red-purple residue. The principles involved in this test were oxidation of purine by concentrated HNO3; condensation reaction of alloxan to form alloxanthin; and neutralization which forms the red purple murexide or the potassium salt of purpurate. In the sample, the red-purple residue did not appear which means that there is the absence of purines in the DNA
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