Pyrimidine

Miescher (reviewed in Dahm 2005). Further work was performed by other chemists, including Phoebus Levene who identified the components of the molecule, including the presence of ribose sugars and phosphate groups, as well as four nucleotide bases; the pyrimidines, cytosine (C), and thymine (T); and the purines, guanine (G), and adenine (A) (Levene 1919). Erwin Chargaff showed that in DNA the amount of adenine nucleotides equalled the number of thymine nucleotides and the number…

strong enough, it is unable to directly affect it (Goodsell). UVB on the other hand retains a strong enough energy to further impact the DNA in cells after going through the atmosphere (Goodsell). UVB directly affects the DNA by attacking the pyrimidine structure in the helix. As a result, bases are changed, covalent bonds are added, or new bonds are formed (Goodsell). The helix undergoes these reactions many times during every second of sunlight exposure or exposure to UVB light. These are…

function without hundreds of pre-existing proteins, but proteins are produced only at the direction of DNA.To produce a protein, the building blocks are amino acids. For DNA and RNA these building blocks are nucleotides, which are composed of purines, pyrimidines, sugars, and phosphoric acid. If amino acids are dissolved in water they do not spontaneously join together to make a protein. That would require an input of energy. If proteins are dissolved in water the chemical bonds between the…

Structure and function have always had a close relationship in biological, chemical and general terms. Often the functionality is dependent upon the structure, for example the villi on the epithelial cells increase the surface area and hence the rate of absorbance of molecules in to cells and the blood stream. DNAs function is highly specific to its structure as even the smallest change to this could cause a long term effect, or even death. Base sequence mutations, errors in replication and…

Construction of DNA, RNA, And Protein By Building Models Introduction Nucleic acids are made of nucleotides. When these nucleic acids form sequences they create either DNA or RNA. DNA and RNA are composed of a phosphate, a sugar, and a nitrogen base. The main difference in RNA and DNA is that uracil replaces the base of thymine in RNA. Proteins are essential to maintaining cells by creating hormones and enzymes, and defending the cell. The arrangement of DNA and RNA bases dictates what protein…

Continuation of our research program which aim to synthesis of new biologically active quinazolin-4-one derivatives [4-8, 22], we synthesized new bromo quinazolinone derivatives substituted at 3rd position with chalcones,pyrazole, isoxazole or thio pyrimidine moiety bearing para chloro phenyl moiety at position 2. 2. Results and discussion 2.1.…

Extra Virgin Olive Oil Impairs UV-Induced Cell Damage in Cancer-Prone Mice INTRODUCTION Ultraviolet radiation produces various wavelengths that are part of the electromagnetic spectrum. The four different UV wavelengths are classified as UVA, UVB, and UVC. UVA produces the longest wavelength at 320-400nm, UVB produces wavelengths from 290-320nm, and UVC wavelengths are the shortest wavelength that is completely absorbed by the ozone layer. However, it is known that…

Introduction Epigenetics, “above-genetics” is concerned with the mechanism that underlies developmental processes and canalization that are neither necessarily transmitted nor brought about by changes in the DNA sequence in both eukaryotes and prokaryotes. At the cellular level it focuses on the developmental process that leads to cell determination and cell differentiation (Jablonka & Raz, 2009). Narrowly defined, epigenetics refers to the scientific approach concerned with changes in the…

1.2 Cellular DNA Damage responses, genomic instability. DNA is the blue print of life and all the information of life processes such as growth, metabolism, reproduction etc are encoded in the sequence of it. Therefore its very important to maintain the genomic integrity of this genetic material, not only to keep away defects in life processes but to pass a faithful information to the next progeny. Integrity of the DNA is usually challenged by both endogenous and exogenous agents who are capable…

James Watson, Francis Crick, Rosalind Franklin and Maurice Wilkins all played a pivotal role in determining the structure of the DNA molecule. The orderly and methodical work at King’s college, London by Rosalind Franklin and Maurice Wilkins provided a more experimental approach, working closely with X-ray diffraction images of DNA, this was juxtaposed to Watson and Cricks who at their Cambridge lab approached research by building physical models, narrowing down possibilities and producing ever…