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Helical Symmetry
Published in Mihai V. Putz, New Frontiers in Nanochemistry, 2020
The functionality of various hierarchically structured materials, like solids, biomolecules or supramolecular assemblies is assured by the particular geometry arrangement of their building blocks (Chung et al., 2011). They possess in many cases highly ordered microscopic structures, like crystals (Hoddeson et al., 1992), co-crystals (Braga et al., 2009), dendrimers (Buhleier et al., 1978; Yates et al., 2005) or coiled peptide chains (Pauling et al., 1951) which often exhibit periodic structures by repeating itself in different directions in the space. The discovery in 1953 of the double helix structure of the DNA by James Watson and Francis Crick (Watson et al., 1953) is considered as the starting point of the modern molecular biology. The functionality of biomolecular structures is given by their three-dimensional shapes, therefore knowing their specific physicochemical properties we can elucidate how these specific functionalities are related to the structure of biomolecules.
Molecular and Carbon Nanoelectronics
Published in Sergey Edward Lyshevski, Nano- and Micro-Electromechanical Systems, 2018
Having covered fullerene-centered nanoelectronics, let us turn our attention to biocentered nanoelectronics. DNA, amino acids, proteins, carbohydrates, and other molecules are composed of carbon atoms bonded to one another as well as to hydrogen, oxygen, nitrogen, sulfur, and phosphorus. These H, O, N, S, and P atoms are common composites of the carbon-based biomolecules and complexes. DNA molecules consist of two polynucleotide chains (strands) that spiral around, forming a double helix. These polynucleotide chains are held together by hydrogen bonds between the paired bases. DNA is a linear double-stranded polymer of four nitrogeneous bases: adenine (A), thymine (T), guanine (G), and cytosine (C). The base-pairing rule (A always pairs with T as A = T, while G always pairs with C as G ≡ C) specifies that two strands of the double helix are complementary (see Figure 8.21).
Nanobiosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
DNA analysis is helpful for understanding many diseases on a molecular level and promises new perspectives for medical diagnosis in the future. The DNA which carries the genetic information is a double helix molecule and the double helix is held together by two sets of forces: hydrogen bonding between complementary base pairs and base-stacking interactions.
Heredity under the Microscope: Chromosomes and the Study of the Human Genome
Published in Annals of Science, 2021
The first time I asked one of the pioneers of medical genetics about the impact of the DNA double helix on their field and he replied, ‘Basically, none’, I was stunned. It was common knowledge that the history of molecular genetics led directly from the double helix, solved in 1953, to the Human Genome Project, with its promise of genetically personalized medicine, announced complete in 2003. But I kept receiving the same answer and eventually the picture clarified. Although the first instance of Mendelian inheritance in humans dates to 1902 – the very origins of genetics as a science – medical genetics, and human genetics more broadly, went nowhere slowly for half a century. While fruit flies, maize, mice, and moulds had their chromosomes stained, counted, and mapped, human chromosomes were just too damned difficult to see and count. In 1953, the biology textbooks all said, mistakenly, that a human cell contained forty-eight chromosomes.
Evaluating direct and indirect effects of low-energy electrons using Geant4-DNA
Published in Radiation Effects and Defects in Solids, 2020
Eunae Choi, Kwon Su Chon, Myong Geun Yoon
The biological effect of ionizing radiation is fundamentally determined by nuclear DNA (1–3). DNA consists of two strands forming a double helix and bases bound to each other by hydrogen bonds. Ionizing radiation results in physical and chemical changes in the cell followed by biological changes causing DNA damage. Major DNA damage includes single and double strand breaks (SSB and DSB) and base damages.(4–6) Such DNA damage leads to cell death, mutation, and carcinogenesis if misrepaired or unrepaired. DSB is the most detrimental of all types of DNA damage (7,8).