Acids deoxyribonucleic

A DNA (deoxyribonucleic acid) molecule formed by two polynucleotide chains consists of nucleotide subunits. There are four types of nucleotide subunits of DNA, which are composed of deoxyribose attached to phosphate groups and four bases adenosine (A), cytosine (C), guanine (G), and thymine (T). These nucleotides are covalently bound to each other via the deox30 ibose and phosphates. One end of the polynucleotide chain has 3 hydroxyl and the other end has 5 phosphate. 

The two chains form double helix as two sugar-phosphate backbones wind around each other as three-dimensional structure. The bases are stacked inside the helix and their hydrophobic structures are very close to each other, whereas the hydrophilic 

In addition to the specificity of the hydrogen bonding between complementary bases, unwounding and rewounding of the double 

---

Thundat T, Warmack R J, Allison D P, Bottomley L A, Lourenco A J and Ferrell T L 1992 Atomic force microscopy of deoxyribonucleic acid strands adsorbed on mica the effect of humidity on apparent width and image contrast J. Vac. Sol. Technol. A 10 630... 

Watson J D and Crick F H C 1953 Genetical implications of the structure of deoxyribonucleic acid Nature 171 964-7... 

Wetzel, R., Zirwer, D., Becker, M. Optical anisotropy of oriented deoxyribonucleic acid films of diffi-rcrit water content. Biopolymers 8 (1969) 391-401... 

The hydroxyl at C 2 m D nbose is absent m 2 deoxy d nbose In Chapter 28 we shall see how derivatives of 2 deoxy d nbose called deoxynbonucleotides are the funda mental building blocks of deoxyribonucleic acid (DNA) the material responsible for stor mg genetic information L Rhamnose is a compound isolated from a number of plants Its carbon chain terminates m a methyl rather than a CH2OH group... 

Nucleic acids are acidic substances present m the nuclei of cells and were known long before anyone suspected they were the primary substances involved m the storage transmission and processing of genetic information There are two kinds of nucleic acids ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) Both are complicated biopolymers based on three structural units a carbohydrate a phosphate ester linkage between carbohydrates and a heterocyclic aromatic compound The heterocyclic aro matic compounds are referred to as purine and pyrimidine bases We 11 begin with them and follow the structural thread... 

Adding nucleotides to the 3 oxygen of an existing structure is called elongation and leads ultimately to a polynucleotide The most important polynucleotides are ribonu cleic acid (RNA) and deoxyribonucleic acid (DNA) As we shall see m later sections the polynucleotide chains of DNA and some RNAs are quite long and contain hundreds of thousands of bases... 

True to their word Watson and Crick followed up their April 25 paper with another on May 30 This second paper Genetical Implications of the Struc ture of Deoxyribonucleic Acid outlines a mechanism for DNA replication that is still accepted as essentially correct... 

Section 28 7 Nucleic acids are polynucleotides present m cells The carbohydrate component is D nbose m ribonucleic acid (RNA) and 2 deoxy d ribose m deoxyribonucleic acid (DNA)... 

DNA (deoxyribonucleic acid) (Section 28 7) A polynucleotide of 2 deoxynbose present in the nuclei of cells that serves to store and replicate genetic information Genes are DNA... 

Schematic diagram of deoxyribonucleic acid (DNA) showing the pairing of nitrogen bases (A-T C-G) between parts of two strands of DNA, the backbone of each strand being composed of alternately linked sugar and phosphate units.

Genes are constructed from sets of deoxyribonucleic acids (DNA), which in turn consist of chains of nucleotides. These chains occur in matched pairs, twisted around each other (a double helix). 

Benzylamine Purine. The purine 6-benzylaminopurine [1214-39-7] (13) is an analogue of the natural product adenine, a component of both deoxyribonucleic acid and ribonucleic acid. It is not employed alone, but rather in combination with the natural products GA and GA to improve the size, weight, and thereby, yield per hm of Red DeHcious apples (10,24,25). Compounds with cytokinin activity were reported in 1913 (26) and asymmetric growth in apples was pubHshed in 1968 (27). 

Nucleic acid (deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)) probes utilize labeled, ie, radioactive, enzymatic, or fluorescent, fragments of DNA or RNA (the probe) to detect complimentary DNA or RNA sequences in a sample. Because the probe is tailored for one specific nucleic acid, these assays are highly specific and very sensitive (45). 

Resonance Raman Spectroscopy. If the excitation wavelength is chosen to correspond to an absorption maximum of the species being studied, a 10 —10 enhancement of the Raman scatter of the chromophore is observed. This effect is called resonance enhancement or resonance Raman (RR) spectroscopy. There are several mechanisms to explain this phenomenon, the most common of which is Franck-Condon enhancement. In this case, a band intensity is enhanced if some component of the vibrational motion is along one of the directions in which the molecule expands in the electronic excited state. The intensity is roughly proportional to the distortion of the molecule along this axis. RR spectroscopy has been an important biochemical tool, and it may have industrial uses in some areas of pigment chemistry. Two biological appHcations include the deterrnination of helix transitions of deoxyribonucleic acid (DNA) (18), and the elucidation of several peptide stmctures (19). A review of topics in this area has been pubHshed (20). 

Liquid Crystalline Structures. In certain ceUular organeUes, deoxyribonucleic acid (DNA) occurs in a concentrated form. Striking similarities between the optical properties derived from the underlying supramolecular organization of the concentrated DNA phases and those observed in chiral nematic textures have been described (36). Concentrated aqueous solutions of nucleic acids exhibit a chiral nematic texture in vitro (29,37). 

Biotechnology is being appHed in the dairy industry. A significant and controversial development is the technique of producing transgenic animals, ie, animals in which hereditary deoxyribonucleic acid (DNA) has been augmented by DNA from another source, using recombinant DNA (rDNA) techniques. 

Nucleic Acids. Phosphoms is an essential component of nucleic acids, polymers consisting of chains of nucleosides, a sugar plus a nitrogenous base, and joined by phosphate groups (43,44). In ribonucleic acid (RNA), the sugar is D-ribose in deoxyribonucleic acids (DNA), the sugar is 2-deoxy-D-ribose. 

---