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investigation 4 on dna in mr. miller's 2nd period bio class

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  1. 1. DNA research paper. Ben Hartman Grant Corrigan Mia FernandezA brief history of DNA and a crucial scientist.DNA is found in every living thing, from humans to microorganisms. Without DNA, wewould all have the same characteristics. The study of DNA was started by a man namedGregor Mendel, in 1900
  2. 2. This discovery was re-discovered by Dr. Barbara McClintock, a geneticist born in 1902. In the study of genetics, they used ornamental corn tohelp them discover how chromosomes carry specific genes to new generations. AtCornell University in the late 1920’s to early 1930’s, the genetics department brought inornamental corn to study. Dr. McClintock started working on identifying and labelingthe 10 chromosomes of the corn. She was able to see the parts of the cornchromosomes by using new microscopic techniques. She spent many years researchingand finally came to a conclusion much different than the popular belief. She discoveredthat genes don’t in fact, stay in one place. They move. She called them “jumping
  3. 3. genes”. She believes that these “jumping genes” caused different appearances inplant’s offspring by either activating or inactivating the gene that controls the color ofthe kernels. Dr. McClintock observed two different kinds of transpositions, which aredissociaters and activators. The dissociaters can “jump” to a different place whensignaled by activators. She concluded that the dissociaters would cause changes andthe nearby genes of the chromosome and the color of the kernels in the ornamentalcorn. She verified this conclusion from multiple and repeated experiments. In 1951, Dr.Barbara McClintock showed her discover to nine groups of scientists from all around theworld at a scientific meeting. Her discovery was not well accepted; the other scientistswere not as amazed as she was and they thought her methods were old fashioned. Theother scientists were using other technologies, such as the electron microscope.Although her methods were out of date, her discovery was ground-breaking.
  4. 4. Her discovery wasn’t really believeduntil the 1970s, when a group of molecular biologists found bits of DNA jumping aroundin bacteria. Later, scientist found these transpositions in other things besides corn.They have discovered that every living thing has transpositions. This finally confirmedthat Dr. McClintock’s theory was right all along.
  5. 5. The modern manipulation of DNA.Ever since the discovery of DNA and genes, the manipulation of them has been asomewhat controversial subject. The technology used in genetic engineering is calledDNA Technology. This technology can be used to cure diseases, to treat geneticdisorders, for the improvement of food crops and much more. Genetic Engineers usetwo main parts of the DNA strand to manipulate genes how they want which are calledrestriction enzymes and cloning vectors
  6. 6. The Restriction Enzymes are used to cut DNA strands into smaller parts which make iteasier for genetic engineers to work with. These restriction enzymes cut the DNA chainsseparately between the G nucleotides and the A nucleotides, therefore creating singlechains of DNA. These “tails” are called sticky ends. The sticky ends can bind togetherwith others so that essentially, two different parts of two different DNA strands can bindtogether making an entirely new strand.After work with restriction enzymes, specific genes can become isolated but cloningvectors must be used to place the new isolated genes and the new strands previouslycombined into an organism. The cloning vector is basically a vessel that is used for thetransportation and cloning from one organism to another. Plasmids, rings of DNA foundin bacteria contain cloning vectors. To use one of these cloning vectors, it has to beremoved from the gene itself. Once the cloning vector is isolated, the plasmid is thencut, removing the unwanted gene. Once the unwanted gene is removed, the “donorgene” or the new gene is added.This remarkable simple process can produce many good things for mankind. It can helpto prevent diseases and in some cases, cure them. Although this process can cause a logof good and fix many problems, some people believe that this is dangerous and almosttampering with the fabric of life itself.
  7. 7. Before this type of genetic engineering, things were created only by nature, which tosome is ideal. Others feel that genetic engineering is a great milestone for science andopens up many new possibilities.Genetic engineering has opened up many possibilities in agriculture and farming alone.Previously, plants and other types of grown foods were at the mercy of theirenvironments and the types of infestations or diseases that could hurt them. Withgenetic engineering they can make “Franken-foods” that can be resistant to theseforces, where without them they would normally die.
  8. 8. How DNA works briefly.DNA molecules consist of tub long chains each. The chains that DNA is made up of is nucleotides.Nucleotides are made up of three different parts: those three parts are- sugar molecule, and that iscalled deoxyribose. The other is a phosphouris atom and that is surrounded by oxygen atoms; and amolecule that is referred to as an nitrogen- containing base because it contains a nitrogen atom.All DNA molecules have an identical sugar base molecule in them that is called deoxyribose sugarphosphate. Nitrogen molecules contain base, however can be one of four kinds, first is calledadenine (A), second is called guanine (G), third is called cytosine ©, and last is called thymine (T).The double helix was discovered by James Watson, and Francis Crick in 1953. They suggested that ifthey made a model of DNA structure. The model proposed was that DNA is composed of twonucleotide chains that wrap around each other to form a double spiral. This “double spiral” shape isnow called a Double Helix.Adenine and guanine combined are called purines. The adenine is made up of NH2, HC, N, NH,C4, and C. Thymine and cytosine combined are called pyrimidines. Bases just like the two listedabove commonly have two rings of carbon and nitrogen atoms. Such as adenine and guanine arecalled purines. Bases that have one ring of carbon and nitrogen atoms such as adenine and guanineare called pyrimidines.RNA is like DNA; it is an nucleic acid made up of repeating nucleotides. The difference betweenDNA and RNA is that RNAs sugar molecules are ribose, where as DNAs sugar molecules are justdeoxribose sugar. A rare part that is in RNA uracil, that is a nitrogen thymine.
  9. 9. There are three different types of RNA, and those three types are called messenger RNA (mRNA),the second is called transfer RNA (tRNA), and the last one is called ribismoal RNA (rRNA). Thereare about 45 variations of (tRNA).