A nucleic acid is a macromolecule composed of chains of monomeric nucleotide. The term macromolecule by definition implies "large Molecule " Nucleotides are Organic compounds that consist of three joined structures a nitrogenous base a Sugar, and a Phosphate group In biochemistry these molecules carry genetic information or form structures within cells. Biochemistry is the study of the chemical processes in living Organisms It deals with the Structure and function of cellular components such as In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by A DNA sequence or genetic sequence is a succession of letters representing the Primary structure of a real or hypothetical DNA Molecule The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called The most common nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units Nucleic acids are universal in living things, as they are found in all cells and viruses. A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable Nucleic acid was first discovered by Friedrich Miescher. Johannes Friedrich Miescher ( 13 August 1844, Basel - 26 August 1895, Davos) was a Swiss Biologist

Artificial nucleic acids include peptide nucleic acid (PNA), Morpholino and locked nucleic acid (LNA), as well as glycol nucleic acid (GNA) and threose nucleic acid (TNA). Nucleic acid analogues are compounds structurally similar ( analog) to naturally occurring RNA and DNA used in medicine and in molecular biology research Peptide nucleic acid (PNA is an artificially synthesized Polymer similar to DNA or RNA and is used in biological research and medical treatments In Molecular biology, a Morpholino is a Molecule used to modify Gene expression. A locked nucleic acid (LNA often referred to as inaccessible RNA is a modified RNA Nucleotide. Glycerol nucleic acid (GNA is a Polymer similar to DNA or RNA but differing in the composition of its "backbone" Threose nucleic acid (TNA is a Polymer similar to DNA or RNA but differing in the composition of its "backbone" Each of these is distinguished from naturally-occurring DNA or RNA by changes to the backbone of the molecule.

Contents 1 Chemical structure 2 Types of nucleic acids 2.1 Ribonucleic acid 2.2 Deoxyribonucleic acid 3 Nucleic acid components 3.1 Nucleobases 3.2 Nucleosides 3.3 Nucleotides and deoxynucleotides 4 See Also 5 External links 6 References

Chemical structure

The term "nucleic acid" is the generic name for a family of biopolymers, named for their role in the cell nucleus. Biopolymers are a class of Polymers produced by living organisms In Cell biology, the nucleus (pl nuclei; from Latin la ''nucleus'' or la ''nuculeus'' "little nut" or kernel is a membrane-enclosed The monomers from which nucleic acids are constructed are called nucleotides. A monomer (from Greek mono "one" and meros "part" is a small Molecule that may become chemically bonded to other Nucleotides are Organic compounds that consist of three joined structures a nitrogenous base a Sugar, and a Phosphate group

Each nucleotide consists of three components: a nitrogenous heterocyclic base, which is either a purine or a pyrimidine; a pentose sugar; and a phosphate group. In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and Purine ( 1) is a heterocyclic Aromatic Organic compound, consisting of a Pyrimidine ring fused to an Imidazole ring Pyrimidine is a Heterocyclic Aromatic Organic compound similar to Benzene and Pyridine, containing two Nitrogen Atoms A pentose is a Monosaccharide with five Carbon Atoms They either have an Aldehyde Functional group in position 1 ( aldopentoses Sugar is a class of edible Crystalline substances mainly Sucrose, Lactose, and Fructose. A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. Nucleic acid types differ in the structure of the sugar in their nucleotides - DNA contains 2-deoxyriboses while RNA contains ribose (where the only difference is the presence of a hydroxyl group). Deoxyribose, also known as D-Deoxyribose and 2-deoxyribose, is an Aldopentose &mdash a Monosaccharide containing five Carbon Ribose (ɹˈaɪbəʊs ɹˈaɪbəɹʊs primarily seen as D-ribose, is an Aldopentose — a Monosaccharide containing five Carbon Hydroxyl in Chemistry stands for a molecule consisting of an Oxygen atom and a Hydrogen atom connected by a Covalent bond. Also, the nitrogenous bases found in the two nucleic acid types are different: adenine, cytosine, and guanine are found in both RNA and DNA, while thymine only occurs in DNA and uracil only occurs in RNA. Adenine is a Purine with a variety of roles in Biochemistry including Cellular respiration, in the form of both the energy-rich Adenosine Cytosine is one of the five main bases found in DNA and RNA. It is a Pyrimidine derivative with a Heterocyclic Aromatic ring Guanine is one of the five main Nucleobases found in the Nucleic acids DNA and RNA, the others being Adenine, Cytosine, Thymine is one of the four bases in the Nucleic acid of DNA that make up the letters ATGC Uracil is a common and naturally occurring Pyrimidine derivative Other rare nucleic acid bases can occur, for example inosine in strands of mature transfer RNA. Inosine is a Nucleoside that is formed when Hypoxanthine is attached to a Ribose ring (also known as a Ribofuranose) via a β-N9- Transfer RNA (abbreviated tRNA) is a small RNA (usually about 74-95 nucleotides that transfers a specific Amino acid to a growing polypeptide chain at

Nucleic acids are usually either single-stranded or double-stranded, though structures with three or more strands can form. A double-stranded nucleic acid consists of two single-stranded nucleic acids held together by hydrogen bonds, such as in the DNA double helix. A chemical bond is the physical process responsible for the attractive interactions between Atoms and Molecules and which confers stability to diatomic and polyatomic In contrast, RNA is usually single-stranded, but any given strand may fold back upon itself to form secondary structure as in tRNA and rRNA. Within cells, DNA is usually double-stranded, though some viruses have single-stranded DNA as their genome. A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable Retroviruses have single-stranded RNA as their genome. A retrovirus is any Virus belonging to the viral family Retroviridae.

The sugars and phosphates in nucleic acids are connected to each other in an alternating chain, linked by shared oxygens, forming a phosphodiester bond. A phosphodiester bond is a group of strong covalent bonds between the phosphorus atom in a Phosphate group and two other Molecules over two In conventional nomenclature, the carbons to which the phosphate groups attach are the 3' end and the 5' end carbons of the sugar. Molecular biologists use several shorthand terms when referring to Nucleic acid molecules such as DNA and RNA, collectively referred to as nucleic This gives nucleic acids polarity. The bases extend from a glycosidic linkage to the 1' carbon of the pentose sugar ring. Bases are joined through N-1 of pyrimidines and N-9 of purines to 1' carbon of ribose through N-β glycosyl bond.

Types of nucleic acids

Ribonucleic acid

Main article: RNA

Ribonucleic acid, or RNA, is a nucleic acid polymer consisting of nucleotide monomers, which plays several important roles in the processes of translating genetic information from deoxyribonucleic acid (DNA) into proteins. Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units RNA acts as a messenger between DNA and the protein synthesis complexes known as ribosomes, forms vital portions of ribosomes, and serves as an essential carrier molecule for amino acids to be used in protein synthesis.

Deoxyribonucleic acid

Main article: DNA

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known The main role of DNA molecules is the long-term storage of information and DNA is often compared to a set of blueprints, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information.

Nucleic acid components

Nucleobases

Main article: Nucleobase

Nucleobases are heterocyclic aromatic organic compounds containing nitrogen atoms. Structure The "skeleton" of adenine An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Nucleobases are the parts of RNA and DNA involved in base pairing. Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known In Molecular biology, two Nucleotides on opposite complementary DNA or RNA strands that are connected via Hydrogen bonds are called Cytosine, guanine, adenine, thymine are found predominantly in DNA, while in RNA uracil replaces thymine. Cytosine is one of the five main bases found in DNA and RNA. It is a Pyrimidine derivative with a Heterocyclic Aromatic ring Guanine is one of the five main Nucleobases found in the Nucleic acids DNA and RNA, the others being Adenine, Cytosine, Adenine is a Purine with a variety of roles in Biochemistry including Cellular respiration, in the form of both the energy-rich Adenosine Thymine is one of the four bases in the Nucleic acid of DNA that make up the letters ATGC Uracil is a common and naturally occurring Pyrimidine derivative Thymine is one of the four bases in the Nucleic acid of DNA that make up the letters ATGC These are abbreviated as C, G, A, T, U, respectively.

Nucleobases are complementary, and when forming base pairs, must always join accordingly: cytosine-guanine, adenine-thymine (adenine-uracil when RNA). In Molecular biology, complementarity is a property of double-stranded Nucleic acids such as DNA and RNA as well as DNARNA duplexes The strength of the interaction between cytosine and guanine is stronger than between adenine and thymine because the former pair has three hydrogen bonds joining them while the latter pair have only two. Thus, the higher the GC content of double-stranded DNA, the more stable the molecule and the higher the melting temperature. DNA denaturation, also called DNA melting, is the process by which double-stranded Deoxyribonucleic acid unwinds and separates into single-stranded strands through

Two main nucleobase classes exist, named for the molecule which forms their skeleton. These are the double-ringed purines and single-ringed pyrimidines. Purine ( 1) is a heterocyclic Aromatic Organic compound, consisting of a Pyrimidine ring fused to an Imidazole ring Pyrimidine is a Heterocyclic Aromatic Organic compound similar to Benzene and Pyridine, containing two Nitrogen Atoms Adenine and guanine are purines (abbreviated as R), while cytosine, thymine, and uracil are all pyrimidines (abbreviated as Y).

Hypoxanthine and xanthine are mutant forms of adenine and guanine, respectively, created through mutagen presence, through deamination (replacement of the amine-group with a hydroxyl-group). Hypoxanthine is a naturally occurring Purine derivative It is occasionally found as a constituent of Nucleic acids where it is present in the Anticodon Xanthine (ˈzænθiːn ˈzænθaɪn] (37-dihydro-purine-26-dione is a Purine base found in most body tissues and fluids and in other organisms In Biology, a mutagen ( Latin, literally origin of change) is a physical or chemical agent that changes the genetic information (usually DNA) These are abbreviated HX and X.

Nucleosides

Main article: Nucleoside

Nucleosides are glycosylamines made by attaching a nucleobase (often referred to simply as bases) to a ribose or deoxyribose (sugar) ring. See also Adenosine triphosphate (ATP Glycosylamine is a biochemical compound consisting of an Amine with a β-N-glycosidic bond to a Carbohydrate. Structure The "skeleton" of adenine Ribose (ɹˈaɪbəʊs ɹˈaɪbəɹʊs primarily seen as D-ribose, is an Aldopentose — a Monosaccharide containing five Carbon Deoxyribose, also known as D-Deoxyribose and 2-deoxyribose, is an Aldopentose &mdash a Monosaccharide containing five Carbon Sugar is a class of edible Crystalline substances mainly Sucrose, Lactose, and Fructose. In short, a nucleoside is a base linked to sugar. The names derive from the nucleobase names. The nucleosides commonly occurring in DNA and RNA include cytidine, uridine, adenosine, guanosine and thymidine. Cytidine is a Nucleoside Molecule that is formed when Cytosine is attached to a Ribose ring (also known as a Ribofuranose) via Uridine is a molecule (known as a Nucleoside) that is formed when Uracil is attached to a Ribose ring (also known as a Ribofuranose) via a β-N1- Adenosine is a Nucleoside composed of a Molecule of Adenine attached to a Ribose sugar molecule ( Ribofuranose) moiety via a β-N9- Guanosine is a Nucleoside comprising Guanine attached to a Ribose ( Ribofuranose) ring via a β-N9- Glycosidic bond. Thymidine (more precisely called deoxythymidine; can also be labelled deoxyribosylthymine, and thymine deoxyriboside) is a Chemical compound When a phosphate is added to a nucleoside (by phosphorylated by a specific kinase enzyme), a nucleotide is produced. Phosphorylation is the addition of a Phosphate (PO4 group to a Protein molecule or a small molecule In Chemistry and Biochemistry, a kinase, alternatively known as a phosphotransferase, is a type of Enzyme that transfers Phosphate Nucleoside analogues, such as acyclovir, are used as antiviral agents. Aciclovir ( INN Nucleoside analogues are a range of antiviral products used to prevent Viral replication in infected cells

Nucleotides and deoxynucleotides

Main article: Nucleotide

A nucleotide consists of a nucleoside and one or more phosphate groups. Nucleotides are Organic compounds that consist of three joined structures a nitrogenous base a Sugar, and a Phosphate group A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. In Organic chemistry, functional groups are specific groups of Atoms within Molecules that are responsible for the characteristic Chemical reactions Nucleotides are the monomers of RNA and DNA, as well as forming the structural units of several important cofactors - CoA, flavin adenine dinucleotide, flavin mononucleotide, adenosine triphosphate and nicotinamide adenine dinucleotide phosphate. A monomer (from Greek mono "one" and meros "part" is a small Molecule that may become chemically bonded to other Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Coenzyme A ( CoA, CoASH, or HSCoA) is a Coenzyme, notable for its role in the synthesis and oxidation of Fatty acids In Biochemistry, flavin adenine dinucleotide ( FAD) is a Redox cofactor involved in several important reactions in Metabolism. Flavin mononucleotide (FMN or riboflavin-5′-phosphate, is produced from Riboflavin (vitamin B2 by the enzyme Riboflavin kinase and Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy Nicotinamide adenine dinucleotide phosphate ( NADP+, in older notation triphosphopyridine nucleotide TPN) is used in anabolic reactions such as Lipid In the cell nucleotides play important roles in metabolism, and signaling. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life.

Nucleotides are named after the nucleoside on which they are based, in conjunction with the number of phosphates they contain, for example:

• Adenine bonded to ribose forms the nucleoside adenosine.
• Adenosine bonded to a phosphate forms adenosine monophosphate. Adenosine monophosphate ( AMP) also known as 5'-adenylic acid, is a Nucleotide that is found in RNA.
• As phosphates are added, adenosine diphosphate and adenosine triphosphate are formed, in sequence. Adenosine diphosphate, abbreviated ADP, is a Nucleotide. It is an Ester of Pyrophosphoric acid with the Nucleoside Adenosine Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy

See Also

• Nucleic acid methods

External links

• Interview with Aaron Klug, Nobel Laureate for structural elucidation of biologically important nucleic-acid protein complexes provided by the Vega Science Trust. Nucleic acid methods are the techniques used to study Nucleic acids ( DNA and RNA

References

• Keith Roberts, Martin Raff, Bruce Alberts, Peter Walter, Julian Lewis and Alexander Johnson, Molecular Biology of the Cell 4th Edition, Routledge, March, 2002, hardcover, 1616 pages, 7. 6 pounds, ISBN 0-8153-3218-1

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