This website uses cookies to ensure you have the best experience. Learn more

Dna. Essay

1038 words - 4 pages

Extracting DNA from the Bacterium Escherichia coliIntroduction Deoxyribonucleic acid is contained in allcells. The structure of DNA makes gene transmission possible. Since genes are segments of DNA, DNAmust be able to make exact copies of itself to enable thenext generation of cells to receive the same genes.The DNA molecule looks like a twisted ladder. Each"side" is a chain of alternating phosphate anddeoxyribose sugar molecules. The "steps" are formed bybonded pairs of purine-pyrimidine bases. DNAcontains four such bases the purines adenine (A) and guanine(G) and the pyrimidines cytosine (C) andthymine (T). The RNA molecule, markedly similar to DNA, usually consists of a single chain. The RNA chaincontains ribose sugars instead of deoxyribose. In RNA, the pyrimidine uracil (U) replaces the thymineofDNA. DNA and RNA are made up of basic units called nucleotides. In DNA, each of these is composed of aphosphate, a deoxyribose sugar, and either A, T, G, or C. RNA nucleotides consist of a phosphate, aribosesugar, and either A, U, G, or C. Nucleotide chains in DNA wind around one another to form a complete twist,or gyre, every tennucleotides along the molecule. The two chains are held fast by hydrogen bonds linking A toT and C to GA always pairs with T (or with U in RNA); C always pairs with G. Sequences of the paired basesare thefoundation of the genetic code. Thus, a portion of a double-stranded DNA molecule might read:A-T C-G G-CT-A G-C C-G A-T. When "unzipped," the left strand would read: ACGTGCA; the right strand: TGCACGT. DNA is the "master molecule" of the cell. It directs the synthesis of RNA. When RNA is beingtranscribed, or copied, from an unzipped segýent of DNA, RNA nucleotides temporarily pair theirbaseswith those of the DNA strand. In the preceding example, the left hand portion of DNA would transcribe astrand of RNA with the base sequence: UGCACGU. Genes and Protein Synthesis A genetic code guides the assembly of proteins. The code ensures that each protein is built fromthe proper sequence of amino acids.Genes transmit their protein-building instructions by transcribing a special type of RNA calledmessengerRNA (mRNA). This leaves the cell nucleus and moves to structures in the cytoplasm calledribosomes,where protein synthesis takes place. Cell biologists believe that DNA also builds a type of RNA calledtransfer RNA, which floatsfreely through the cell cytoplasm. Each tRNA molecule links with a specificamino acid. When needed forprotein synthesis, the amino acids are borne by tRNA to a ribosome. TheGenetic Code Experimental evidence indicates that the genetic code is a "triplet" code; that is, each seriesofthree nucleotides along the DNA molecule orders where a particular amino acid should be placed in agrowing protein molecule. Three-nucleotide units on an mRNA strand for example UUU, UUG, and GUU arecalledcodons. The codons, transcribed from DNA, are strung out in a sequence to form mRNA. According to thetriplet theory, tRNA...

Find Another Essay On DNA.

DNA Lab Essay

548 words - 2 pages Bio 181Lap report#12DNA is a hereditary double helix strands that present in the nucleus of living cells. DNA acts as the blueprint for all of the proteins synthesized by that cell. There are many chromosomal regions that vary widely between individuals called polymorphic DNA (poly="many", morph="form"). These regions may or may not encode proteins. By examining several of these polymorphic regions within a person's DNA, a DNA "fingerprint" is

DNA Profiling Essay

1445 words - 6 pages From cases such as OJ Simpson to Chandra Levy, DNA profiling also called DNA fingerprinting or DNA typing has played a major role in the criminal justice system. The law enforcement community uses DNA profiling to rule out or identify suspects. Unlike hair microscopy, bite mark comparisons, shoe print comparisons, and firearm tool mark analysis, DNA typing has been developed through massive scientific research and has undergone meticulous

DNA Technologies

1061 words - 4 pages The structure of DNA was discovered in 1953 and revealed to the world by James Watson and Francis Crick.1 Since then, there has been a whirlwind of activity and discovery in the fields associated with DNA. We have found that DNA is not only a set of instructions for the body, but that it also contains a lot of information about the individual who “owns” the DNA. As it is rapidly becoming cheaper and easier to process DNA, it is becoming more

DNA Profiling

868 words - 4 pages DNA profiling has been one of the biggest advances in technology and science in the 20th century due to its efficiency in the identification of individuals. It is commonly used by forensics scientist for identification of suspects or individuals in crime scenes. DNA profiling as it is today, was developed by two independent studies in molecular biology that occur during the same period of time, in two different places, and by two different

Dna Replication

2179 words - 9 pages DNA REPLICATION WHAT IS DNA? DNA is a molecule that has a repeating chain of identical five-carbon sugars (polymers) linked together from head to tail. It is composed of four ring shaped organic bases (nucleotides) which are Adenine (A), Guanine (G), Cytosine (C) and Thymine (T). It has a double helix shape and contains the sugar component deoxyribose. THE PROCESS OF DNA REPLICATION How DNA replicates is quite a simple process. First, a


1829 words - 7 pages Chi Le og Thomas Rasmussen Svendborg Gymnasium Biologi Rapport Afleveres den 16/01-02 Biologi RapportomhandlendeDNA-elektroforeseUdarbejdet i samarbejde mellemChi Le, 2. BI/1Thomas Rasmussen, 2. BI/2Formål:Formålet med dette forsøg er først og fremmest at bestemme tilstedeværelsen af vores plasmid DNA, for derefter at bestemme størrelsen af dette ved hjælp af enDNA-eletroforese og

DNA History

757 words - 3 pages There are defining moments in everybody's life, but right now the light shines on genetic information of each cell, DNA. Scientists have been trying to trace each letter of the genome's biochemical code for the last decade. In the Washington Post article, For DNA, a Defining Moment by Rick Weiss, tells us that a company in Rockville, MD and a team of scientists say that they have completed the task of decoding DNA. They will be announcing to the

DNA Experiments

580 words - 2 pages 1.Experiments by the following scientists provided critical information concerning DNA. Fully describe 2 of these 3 classical experiments and indicate how each provided evidence for the chemical nature of the gene.a. Hershey and Chase- bacteriophage replicationThey prepared two separate samples of viruses, one in which the DNA (contains phosphorus but no sulfur) was labeled with a radioactive isotope, 32P, and the other in which the protein

DNA Fingerprinting

674 words - 3 pages biochemistry; he stayed there to complete his PhD in genetics in 1975. In his research, he paired up with Richard Flavell in order to attempting to isolate and purify mammalian genes, specifically the rabbit β-globin gene. They ultimately failed but discovered the composition of eukaryotic DNA: introns, which was quite the discovery being only 27 years old at the time. It was now 1977 and the next question was, "What's next to come?&quot

DNA electropherises

989 words - 4 pages - -DNA electrophoreses is a process in which a DNA strand is cut by a restriction enzyme at a certain point so it can be measured and compared with other DNA. The purpose of the lab was to determine the father of a child by comparing the child's DNA with that of the mother and two possible fathers. The child's DNA fits a combination of the real father and mother.Electrophoresis begins with the pouring of the gel. The gel is an auger poured into

DNA Testing

1604 words - 6 pages The criminal justice system is not perfect. Throughout the process there can be many errors that can result in the incarceration of an innocent person. There are examples of this in the case of Gerald Wayne Davis. Faulty eyewitness testimony and double jeopardy are two of errors that will be reviewed in this case. The focus is the use of unreliable scientific evidence. In the past non-DNA testing of evidence was use to prove guilt or innocence

Similar Essays

Dna Fingerprinting Essay

930 words - 4 pages “Traditionally, the term “fingerprint” refers to the patterns, which are highly characteristic for any human individual, of the ridged skin of the distal finger phalanges…’fingerprinting’ has also been used for the electrophoretic and chromatographic characterization of proteins and, more recently, of deoxyribonucleic acid (DNA) molecules” (2) DNA fingerprinting has become a big part of our criminal system. Being able to show that someone

Dna Extraction Essay

1151 words - 5 pages DNA isolation is a process of purification of DNA from sample using a combination of physical and chemical methods. The first isolation of DNA was done in 1869 by Friedrich Miescher. DNA stands for deoxyribose nucleic acid. It consists of two strands that wrap around each other in a shape called a double helix. There are also four bases that make up DNA that are adenine, guanine, cytosine, and thymine. Each base pairs up its specific such that

Ancient Dna Essay

1038 words - 5 pages Ostelogical analysis is a very important process in understand our past. There are so many things that bones could tell us; the range of knowledge is great, we can determine where the remains came from their approximate age, their sex, their diet and even their death. There are so many different kinds of analysis that can be done from using ancient DNA to analyzing Stable Isotopes. Analysis of Ancient DNA hold an important key to solving the

Dna Fingerprinting Essay

825 words - 3 pages Donald Hall DNA Fingerprinting 1 Running head: DNA FINGER PRINTING DNA Fingerprinting in the criminal justice system Donald Hall American Military University DNA Fingerprinting 2 Abstarct DNA fingerprinting is a powerful technology that has revolutionized