Extracting DNA from Bananas
In the Lab: Extracting DNA from Bananas, DNA was removed from bananas that had been blended with water in order to examine how DNA is seen from the naked eye. DNA stands for deoxyribonucleic acid, which is a nucleic acid that contains the sugar deoxyribose. DNA is made up of a series of monomers called nucleotides. Each nucleotide has three parts: a deoxyribose molecule, a phosphate group, and a nitrogenous base. In addition, there are four kinds of nitrogenous bases in DNA. Two of the nitrogenous bases, adenine and guanine, belong to a group of compounds known as purines. The remaining two bases, cytosine and thymine, are known as pyrimidines. The actual DNA structure is seen as a double helix in which two strands are wound around each other. Each strand is made up of a chain of nucleotides. The two strands are held together by hydrogen bonds between adenine and thymine and between guanine and cytosine. In 1944, a group of scientists led by Canadian biologist Oswald Avery performed an experiment that would determine which molecule in a heat-killed bacterium was most important for transformation to occur. Avery and the other scientists discovered that DNA is the nucleic acid that stores and transmits the genetic information from one generation of an organism to the next. Thus, DNA is present in all living organisms. It holds the instructions necessary for the organism to grow and function, and is passed on from generation to generation through heredity.
During the procedure of the lab, a ratio of one banana per one cup (250 milliliters) of distilled water had to be mixed together in a blender. The solution had to be blended for 15 to 20 seconds, until it became a dense mixture. In a separate five-ounce cup, a solution consisting of one teaspoon of shampoo and two pinches of salt was made. 20 milliliters (four teaspoons) of distilled water was then added to the mixture. Then the salt and shampoo had to be...
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