Dna Essay

The four bases found in DNA are adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T). A fifth pyrimidine base, called uracil (U), usually takes the place of thymine in RNA and differs from thymine by lacking a methyl group on its ring.

This paper explores the history and some interesting facts about DNA. The last couple centuries have seen an exponential growth in our knowledge of DNA. The history of the DNA can be traced back to multiple devoted scientist. This article attempts to summarize, and review the basic history of DNA while providing some fascinating information about it.

In the early 1950s, the race to find the structure of DNA was in full swing. The search was being conducted at three different colleges. At the California Institute of Technology, Linus Pauling,

Furthermore, DNA is found in large quantities within the eukaryotic cell. Human cells alone have around 1000 times more DNA than typical bacteria [Alberts, c1989, p.23]. DNA, both on its own and with other molecules, plays a huge role in the making of an organism, from the importance of its chiral helical structure and its main functions, to the vast vicinity of error and inaccuracy that a small change to the genomic sequence can cause. It is the foundation upon which an organism is built and the main contributor to an organisms genotype and phenotype. But what are the constituents of DNA and can it

Two scientists from Cambridge University named James Watson and Francis Crick were the first ones to actually build the actual structure of the DNA molecule. In building their DNA molecule, they discovered that there were two different types of bases, purines and pyrimidines. Purines were the larger of the two types of bases, and are the double ringed structures [example of nucleotides that fit in this category are adenine (A) and guanine (G)]. Pyrimidines were the smaller of the two types of bases, and are the only single ringed structures [example of nucleotides that fit in this category are cytosine (C) and thymine (T)]. The two scientists also discovered that in the DNA molecule, only two base pairings of nucleotides are possible, adenine (A) with guanine (G) and thymine (T) with cytosine (C). This is because of the improper forming of hydrogen bonds. In a G-C pairing, three hydrogen bonds are formed whereas in an A-T pairing, only two hydrogen bonds are formed.

When analyzing DNA it is important to understand it and all the chemicals that it is made of. The first thing that’s important to know is simply what DNA stands for, which is deoxyribonucleic acid. The chemical units are called nucleotides, and each nucleotide has a compound of phosphate sugar which is the backbone, and a sugar deoxyribose. The Phosphates and sugars are the same in all nucleotides but the one thing that is different would be the bases. DNA bases are cytosine, thymine, adenine, and guanine. Each base has specific partner, for example Cytosine will always pair with guanine. And Thymine will always pair with adenine.

Purpose The main purpose of this experiment was to test and observe how DNA molecules are being tested or separated. Introduction The final goal of this lab was to successfully measure the size of different samples of DNA placing each samples into a well in agarose gel and running a current through a charged chamber.

The Eppendorf tube was then placed within a centrifuge for 10 minutes to separate the insoluble DNA from the rest of the solution. When the 10 minutes were up, a DNA “pellet” appeared at the bottom of the Eppendorf tube and a pipet was used to decant the solution. Once as much liquid was removed from the Eppendorf tube as possible, 1 mL of 70% ethanol was added to the tube, and it was inverted another 5 times. The sample was then placed within the centrifuge for another 5 minutes at maximum speed. The DNA pellet should still be visible within the Eppendorf tube and using a pipet, the ethanol was decanted from the Eppendorf tube.

The base pairs are very specific on which two can bond together based on the number of rings that they have. Adenine and Guanine are purines, meaning they are composed of two rings. Thymine and Cytosine are pyrimidines which means they are composed of one ring. Purines always bond with pyrimidines, therefore Adenine always bonds with Thymine, and Guanine always bonds with Cytosine. The base pairs are complementary, and almost fit together like a lock and key (CK-12 Foundation, 2017). These nitrogenous bases are bonded together with 1 hydrogen bond. The bases are located in the center of the DNA strand in a specific pattern according to the DNA they are apart of. The name for the base Adenine comes from a greek word “aden” meaning internal gland, and a chemical suffix “ine”. Another base, Thymine, gets its name from thymic acid which it was isolated from, obtained from the thymus gland with the chemical suffix “ine”. Guanine gets its name from guano which the chemical was first isolated from, and the chemical suffix “ine”. Lastly, Cytosine gets its name from “cyto” meaning cell, along with the chemical suffix “ine” that also makes up the other nitrogenous bases (Online Eytmology Dictionary,

Allowing the annual report of the National DNA Database Strategy Board as of 2012-2013, NDNAD helps the law enforcement in giving worthful information that will lead in determining the suspect and solve crime cases. However, sometimes the crime doesn’t solve and more evidence needs to be collecting to secure a conviction but in dealing with NDNAD it provides the police of its needed information for DNA matches.

It is with these free coordination sites of the metal that the proteins, acting as Lewis bases, will interact with and bind to the metal chelate to form a metal-protein complex. In IMAC, the interaction of the electron donating group, Lewis base, on the surface of a protein and the accessible coordination sites from the metal ion, interact which results in the binding of proteins to metal ions. (Nes, 1999) Certain amino acids exposed on the protein’s surface are responsible for the binding. Histidine has the strongest affinity for metal ions while tryptophan and cysteine are also involved in the binding of proteins in IMAC. The strong metal affinity of these amino acids can be attributed to their functional groups: thiol in cysteine, indoyl in tryptophan and imdizole in histidine. Binding of the protein product to an IMAC resin is specific for the amino acid targeted by the affinity ligand. This general binding mechanism is attributed to the interaction of the amino acid group and the affinity ligand. The affinity ligand does not possess the ability to discriminate between multiplicities of the target amino acid and therefore will bind proteins containing single and multiple

Dequalinium (DQA) is a dicationic amphiphilic compound that self-assembles and forms vesicle-like aggregates of diameters between 70 and 700 nm upon sonication; known as DQAsomes(33). Owing to their positive charge and mitochondriotropic properties, DQAsomes could bind or entrap various drugs and DNA and transport them to mitochondria(41). A strong interaction was demonstrated between DQAsomes and plasmid DNA(57), in addition, the formed complex effectively protects DNA from digestion by nucleases(58). Moreover, it was demonstrated that DQAsome complexes with DNA can enter cells, approach mitochondria and release the bound DNA after interaction with the mitochondrial membrane(59). Weissig et al demonstrated that DNA complexed with DQA formed

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The absorption spectrum of probes L1 and L2 (40 μM) were investigated in the presence of metals ions in DMSO solvent. As shown in Fig. 1, Schiff base L1 exhibited absorption band at 269 nm, 310 nm, 323 nm and 347 nm; and L2 at 264 nm, 319 nm, 341 nm, 439 nm and 462 nm, that may be attributed to π-π* charge transfer transition. However, no remarkable changes were observed in absorption spectra after the addition of 1 equivalent various metal ions such as Ag(I), K(I), Li(I) Na(I), Co(II), Cu(II), Cd(II), Pb(II), Mg(II), Hg(II), Mn(II), Al(III), Cr(III), Gd(III) and Nd(III) ions. Interestingly upon the addition of zinc and nickel ions to the probe L1 absorbance peak shifted to higher wavelength (red shift) from 347 nm to 413 nm and 410 nm, respectively. Thus, L1-Zn(II) and L1+Ni(II) complexes exhibited color change from colorless to intense yellow color. Similarly, the addition of Fe(III) and UO2(II) to the probe L2, absorbance peak lead to decrease at 439/462 nm while new peak appear at 355 nm and 366/ 515 nm, respectively. Consequently, the absorbance peaks of L2-Fe(III) complexes shifted to UV-region, thus light yellow color turned to colorless, and in case of L2-UO2(II) complex absorbance peak showed red shift effect, that resulted in dark yellow color (Fig. 2a and b). Thus, absorption spectral changes were enabled to detect Ni(II), Zn(II), Fe(III) and UO2(II) as a naked eye

Due to the DNA’s specificity, samples can be utilised for identification. DNA is a nucleic acid composed of deoxyribose sugar bound to a phosphate group and one of four nitrogenous bases (adenine, guanine, cytosine and thymine). Each section of these three components are referred to as nucleotides, which are joined to the phosphate or sugar of another nucleotide by strong covalent bonds to form a backbone. The nitrogenous bases are joined to complimentary bases of another nucleotide (adenine with thymine, guanine with cytosine) to create a double stranded molecule (Figure 2). To complete the double helical structure, the molecule coils to compact it’s contents. DNA molecules can contain up to two million base pairs, with a human genome containing approximately 3 million base pairs. The random assortment of nitrogenous bases as well as the numerous mutations within certain DNA sequences, results in genetically diverese DNA molecules and genomes between individials.