NationMaster - Encyclopedia: Ribonucleic acid

Ribonucleic acid (RNA) is a nucleic acid consisting of a string of covalently-bound nucleotides. It is biochemically distinguished from DNA by the presence of an additional hydroxyl group, attached to each pentose ring. While RNA usually contains uracil instead of thymine, this is not always true, for example in transfer RNA. One of the main functions of RNA is to copy genetic information from DNA (via transcription) and then translate it into proteins (by translation). A nucleic acid is a complex, high-molecular-weight biochemical macromolecule composed of nucleotide chains that convey genetic information. ... Generally, string is a thin piece of fiber which is used to tie, bind, or hang other objects. ... Jump to: navigation, search Covalently bonded hydrogen and carbon in a molecule of methane. ... A nucleotide is a monomer or the structural unit of nucleotide chains forming nucleic acids as RNA and DNA. A nucleotide consists of a heterocyclic nucleobase, a pentose sugar (ribose or deoxiribose), and a phosphate or polyphosphate group. ... Biochemistry is the chemistry of life, a bridge between biology and chemistry that studies how complex chemical reactions give rise to life. ... Jump to: navigation, search Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and many viruses). ... Hydroxide is a functional group consisting of oxygen and hydrogen: -O−H It has a charge of 1-. The term hydroxyl group is used when the functional group -OH is counted as a substituent of an organic compound. ... Pentose - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Uracil is one of the four RNA nucleobases, replacing thymine as found in DNA. Just like thymine, uracil can form a base pair with adenine via two hydrogen bonds, but it lacks the methyl group present in thymine. ... Thymine, also known as 5-methyluracil, is a pyrimidine nucleobase. ... Transfer RNA (abbreviated tRNA) is a small RNA chain (74-93 nucleotides) that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. ... Genetics (from the Greek genno Î³ÎµÎ½Î½ÏŽ= give birth) is the science of genes, heredity, and the variation of organisms. ... Jump to: navigation, search Information is a word which has many different meanings in everyday usage and in specialized contexts, but as a rule, the concept is closely related to others such as data, instruction, knowledge, meaning, communication, representation, and mental stimulus. ... Jump to: navigation, search Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and many viruses). ... Jump to: navigation, search Transcription is the process through which a DNA sequence is enzymatically copied by an RNA polymerase to produce a complementary RNA. In the case of protein-encoding DNA, transcription is the beginning of the process that ultimately leads to the translation of the genetic code (via... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Translation in the cytoplasm; tRNA carries amino acids which are added to the growing peptide chain in the ribosome. ...

Chemical structure

RNA has five different bases: adenine, guanine, cytosine, uracil, and more rarely thymine. The first three are the same as those found in DNA, but uracil usually replaces thymine as the base complementary to adenine. Exceptions include transfer RNA, which always has thymine on one of its loops. This may be because uracil is energetically less expensive to produce. In DNA, however, uracil is readily produced by chemical degradation of cytosine, so having thymine as the normal base makes detection and repair of such incipient mutations more efficient. Thus, uracil is appropriate for RNA, where quantity is important but lifespan is not, whereas thymine is appropriate for DNA where maintaining sequence with high fidelity is more critical. Image File history File links Thymine and Uracil were incorrectly depicted in the previous version. ... Image File history File links Thymine and Uracil were incorrectly depicted in the previous version. ... Jump to: navigation, search Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and many viruses). ... Adenine is one of the two purine nucleobases used in forming nucleotides of the nucleic acids DNA and RNA. In DNA, adenine (A) binds to thymine (T) via two hydrogen bonds to assist in stabilizing the nucleic acid structures. ... Guanine is one of the five main nucleobases found in nucleic acids (, DNA and RNA). ... Cytosine is one of the 5 main nucleobases used in storing and transporting genetic information within a cell in the nucleic acids DNA and RNA. It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at... Uracil is one of the four RNA nucleobases, replacing thymine as found in DNA. Just like thymine, uracil can form a base pair with adenine via two hydrogen bonds, but it lacks the methyl group present in thymine. ... Thymine, also known as 5-methyluracil, is a pyrimidine nucleobase. ... Transfer RNA (abbreviated tRNA) is a small RNA chain (74-93 nucleotides) that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. ...

Comparison to DNA

Structurally, RNA is indistinguishable from DNA except for the critical presence of a hydroxyl group attached to the pentose ring in the 2' position (DNA has a hydrogen atom rather than a hydroxyl group). This hydroxyl group makes RNA less stable than DNA because it makes hydrolysis of the phosphosugar backbone easier. Molecular biologists use several shorthands when referring to nucleic acid molecules such as DNA and RNA, collectively referred to as nucleic acid nomenclature. ...

Synthesis

Synthesis of RNA is usually catalyzed by an enzyme, RNA polymerase, using DNA as a template. Initiation of synthesis begins with the binding of the enzyme to a promoter sequence in the DNA (usually found "upstream" of a gene). The DNA double helix is unwound by the helicase activity of the enzyme. The enzyme then progresses along the template strand in the 3' -> 5' direction, synthesizing a complementary RNA molecule. The DNA sequence also dictates where termination of RNA synthesis will occur. Jump to: navigation, search Ribbon diagram of the catalytically perfect enzyme TIM. Factor D enzyme crystal prevents the immune system from inappropriately running out of control. ... The enzyme RNA polymerase or RNAP is a nucleotidyltransferase that polymerises ribonucleotides in accordance with the information present in DNA. RNA polymerase enzymes are essential and are found in all nucleated cells of all organisms. ... Jump to: navigation, search Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and many viruses). ... In genetics, a promoter is a DNA sequence that enables a gene to be transcribed. ... Jump to: navigation, search Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and many viruses). ... Jump to: navigation, search Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and many viruses). ... Helicase is an enzyme vital to all living organisms. ...

RNA world hypothesis

The RNA world hypothesis proposes that the universal ancestor to all life relied on RNA both to carry genetic information (like DNA does now) and to catalyze biochemical reactions like an enzyme. In effect, RNA was, before the emergence of the first cell, the dominant, and probably the only, form of life. This hypothesis is inspired by the fact that retroviruses use RNA as their sole genetic material, and performed information-storing tasks. RNA can also act like a catalyst, a task mainly done by proteins today. There are several ribozymes, catalytic RNAs, that have been discovered, and peptide bond formation in the ribosome is carried out by an RNA-derived ribozyme. From this perspective, retroviruses and ribozymes are remnants, or molecular fossils, left over from that RNA world. Assuming that DNA is better suited for storage of genetic information and proteins are better suited for the catalytic needs of cells, one would expect reduced use of RNA in cells, and greater use of DNA and proteins. The RNA world hypothesis proposes that RNA was actually the first life-form on earth, later developing a cell membrane around it and becoming the first prokaryotic cell. ... Jump to: navigation, search Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, sometimes called the building blocks of life. ... Jump to: navigation, search Genera Alpharetrovirus Betaretrovirus Gammaretrovirus Deltaretrovirus Epsilonretrovirus Lentivirus Spumavirus A Retrovirus is a virus which has a genome consisting of two plus sense RNA molecules, which may or may not be identical. ... Jump to: navigation, search A ribozyme (from ribonucleic acid enzyme, also called RNA enzyme) is an RNA molecule, that catalyzes a chemical reaction. ... Diagram showing the π-bonded amino acids and the point of rotation A peptide bond is a chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, releasing a molecule of water (H2O). ... Jump to: navigation, search Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... Jump to: navigation, search A ribozyme (from ribonucleic acid enzyme, also called RNA enzyme) is an RNA molecule, that catalyzes a chemical reaction. ...

Biological role

In genetics, splicing is a modification of genetic information prior to translation. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista A eukaryote (also spelled eucaryote) is an organism with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista A eukaryote (also spelled eucaryote) is an organism with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Jump to: navigation, search Cytoplasm is a homogeneous, generally clear jelly-like material that fills cells. ... Translation in the cytoplasm; tRNA carries amino acids which are added to the growing peptide chain in the ribosome. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... RNA interference (RNAi) is a mechanism in molecular biology where the presence of certain fragments of double-stranded RNA (dsRNA) interferes with the expression of a particular gene. ... Jump to: navigation, search Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... Translation in the cytoplasm; tRNA carries amino acids which are added to the growing peptide chain in the ribosome. ...

Messenger RNA (mRNA)

Main article: Messenger RNA Jump to: navigation, search The life cycle of an mRNA in a eukaryotic cell. ...

Messenger RNA is RNA that carries information from DNA to the ribosome sites of protein synthesis in the cell. Once mRNA has been transcribed from DNA, it is exported from the nucleus into the cytoplasm (in eukaryotes mRNA is "processed" before being exported), where it is bound to ribosomes and translated into protein. After a certain amount of time the message degrades into its component nucleotides, usually with the assistance of RNases. Jump to: navigation, search Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and many viruses). ... Jump to: navigation, search Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista A eukaryote (also spelled eucaryote) is an organism with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Jump to: navigation, search Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... Ribonuclease (RNase) is an enzyme that catalyzes the breakdown of RNA into smaller components. ...

Transfer RNA (tRNA)

Main article: Transfer RNA Transfer RNA (abbreviated tRNA) is a small RNA chain (74-93 nucleotides) that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. ...

Transfer RNA is a small RNA chain of about 74-93 nucleotides that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. It has sites for amino-acid attachment and an anticodon region for codon recognition that binds to a specific sequence on the messenger RNA chain. It is a type of non-coding RNA. A nucleotide is a monomer or the structural unit of nucleotide chains forming nucleic acids as RNA and DNA. A nucleotide consists of a heterocyclic nucleobase, a pentose sugar (ribose or deoxiribose), and a phosphate or polyphosphate group. ... Jump to: navigation, search In chemistry, an amino acid is any molecule that contains both amino and carboxylic acid functional groups. ... Peptides are the family of molecules formed from the linking, in a defined order, of various amino acids. ... Jump to: navigation, search Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... Translation in the cytoplasm; tRNA carries amino acids which are added to the growing peptide chain in the ribosome. ... An anticodon is a unit made up of nucleotides that plays an important role in various DNA cycles, including DNA transcription. ... RNA codons. ... Jump to: navigation, search The life cycle of an mRNA in a eukaryotic cell. ... A non-coding RNA (ncRNA) is any RNA molecule that functions without being translated into a protein. ...

Non-coding RNA or "RNA genes"

Main article: Non-coding RNA A non-coding RNA (ncRNA) is any RNA molecule that functions without being translated into a protein. ...

RNA genes (sometimes referred to as non-coding RNA or small RNA) are genes that encode RNA that is not translated into a protein. The most prominent examples of RNA genes are transfer RNA (tRNA) and ribosomal RNA (rRNA), both of which are involved in the process of translation. However, since the late 1990s, many new RNA genes have been found, and thus RNA genes may play a much more significant role than previously thought. Translation in the cytoplasm; tRNA carries amino acids which are added to the growing peptide chain in the ribosome. ... Transfer RNA (abbreviated tRNA) is a small RNA chain (74-93 nucleotides) that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. ... A non-coding RNA (ncRNA) is any RNA molecule that functions without being translated into a protein. ... Jump to: navigation, search // Events and trends The 1990s are generally classified as having moved slightly away from the more conservative 1980s, but otherwise retaining the same mindset. ...

In the late 1990s and early 2000, there has been persistent evidence of more complex transcription occurring in mammalian cells (and possibly others). This could point towards a more widespread use of RNA in biology, particularly in gene regulation. A particular class of non-coding RNA, micro RNA, has been found in many metazoans (from Caenorhabditis elegans to Homo sapiens) and clearly plays an important role in regulating other genes. Jump to: navigation, search Orders Subclass Multituberculata (extinct) Plagiaulacida Cimolodonta Subclass Palaeoryctoides (extinct) Subclass Triconodonta (extinct) Subclass Placentalia Afrosoricida Artiodactyla Carnivora Cetacea Chiroptera Creodonta (extinct) Dermoptera Desmostylia (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Litopterna (extinct) Macroscelidea Notoungulata (extinct) Perissodactyla Pholidota Primates Proboscidea Rodentia Scandentia Sirenia Tubulidentata Xenarthra Subclass Marsupialia Dasyuromorphia... Gene regulation is the general term for cellular control of protein synthesis at the DNA-RNA transcription step. ... The title given to this article is incorrect due to technical limitations. ... Binomial name Caenorhabditis elegans Maupas, 1900 Caenorhabditis elegans (pronounced see-no-rab-DYE-tis) is a free-living nematode (a roundworm), about 1 mm in length, which lives in a temperate soil environment. ... Human beings are defined variously in biological, spiritual, and cultural terms, or in combinations thereof. ...

Double-stranded RNA

Double-stranded RNA (or dsRNA) is RNA with two complementary strands, similar to the DNA found in all "higher" cells. dsRNA forms the genetic material of some viruses. In eukaryotes, it may play a role in the process of RNA interference and in microRNAs. Jump to: navigation, search A virus is a nonliving small particle that infects cells in biological organisms. ... RNA interference (RNAi) is a mechanism in molecular biology where the presence of certain fragments of double-stranded RNA (dsRNA) interferes with the expression of a particular gene. ... The title given to this article is incorrect due to technical limitations. ...

See also

Category: RNA Genetics (from the Greek genno Î³ÎµÎ½Î½ÏŽ= give birth) is the science of genes, heredity, and the variation of organisms. ... Jump to: navigation, search Molecular biology is the study of biology at a molecular level. ... The RNA Ontology Consortium is an international organization whose purpose is to create a standard vocabulary for studying ribonucleic acid. ... Spanish stamps (2003) showing both Spanish laureates: Ochoa and RamÃ³n y Cajal. ... Antisense mRNA is an mRNA transcript that is complementary to endogenous mRNA. It is the noncoding strand complementary to the coding sequence of mRNA. Introducing a transgene coding for antisense mRNA is a strategy used to block expression of a gene of interest. ... A nucleic acid is a complex, high-molecular-weight biochemical macromolecule composed of nucleotide chains that convey genetic information. ... Adenine Guanine Thymine Cytosine ... Adenine is one of the two purine nucleobases used in forming nucleotides of the nucleic acids DNA and RNA. In DNA, adenine (A) binds to thymine (T) via two hydrogen bonds to assist in stabilizing the nucleic acid structures. ... Thymine, also known as 5-methyluracil, is a pyrimidine nucleobase. ... Uracil is one of the four RNA nucleobases, replacing thymine as found in DNA. Just like thymine, uracil can form a base pair with adenine via two hydrogen bonds, but it lacks the methyl group present in thymine. ... Guanine is one of the five main nucleobases found in nucleic acids (, DNA and RNA). ... Cytosine is one of the 5 main nucleobases used in storing and transporting genetic information within a cell in the nucleic acids DNA and RNA. It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at... Purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring. ... Pyrimidine is a heterocyclic aromatic organic compound, which is similar to benzene and pyridine and that contains two nitrogen atoms at positions 1 and 3 of the six-membered ring. ... Nucleosides are glycosylamines made by attaching a nucleobase to a ribose ring. ... The chemical structure of adenosine Adenosine is a nucleoside comprised of adenine attached to a ribose (ribofuranose) moiety via a Î²-N9-glycosidic bond. ... The chemical compound 5-methyluridine (also called ribosylthymine, thymine riboside, and m5u) is a nucleoside type of nucleic acid. ... 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-glycosidic bond. ... Guanosine is a nucleoside comprising guanine attached to a ribose (also known as a ribofuranose) ring via a β-N9-glycosidic bond. ... Cytidine is a molecule (known as a nucleoside) that is formed when cytosine is attached to a ribose ring (also known as a ribofuranose) via a β-N1-glycosidic bond. ... The chemical structure of adenosine Adenosine is a nucleoside formed when adenine is attached to a ribose ring (also known as a ribofuranose) via a β-N9-glycosidic bond. ... Deoxythymidine is a molecule (known as a nucleoside) that is formed when thymine is attached to a deoxyribose ring (also known as a deoxyribofuranose) via a Î²-N1-glycosidic bond. ... 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-glycosidic bond. ... Guanosine is a molecule (known as a nucleoside) that is formed when guanine is attached to a ribose ring (also known as a ribofuranose) via a β-N9-glycosidic bond. ... Cytidine is a molecule (known as a nucleoside) that is formed when cytosine is attached to a ribose ring (also known as a ribofuranose) via a β-N1-glycosidic bond. ... Ribose Ribose is a five carbon sugar (pentose) that is critical to living creatures. ... Jump to: navigation, search Deoxyribose Deoxyribose, also known as D-Deoxyribose and 2-deoxyribose, is an aldopentose â€” a monosaccharide containing five carbon atoms, and including an aldehyde functional group. ... A nucleotide is a monomer or the structural unit of nucleotide chains forming nucleic acids as RNA and DNA. A nucleotide consists of a heterocyclic nucleobase, a pentose sugar (ribose or deoxiribose), and a phosphate or polyphosphate group. ... Adenosine monophosphate, also known as 5-adenylic acid and abbreviated AMP, is a nucleotide that is found in RNA. It is an ester of phosphoric acid with the nucleoside adenosine. ... Uridine monophosphate, also known as 5-uridylic acid and abbreviated UMP, is a nucleotide that is found in RNA. It is an ester of phosphoric acid with the nucleoside uridine. ... Guanosine monophosphate, also known as 5-guanidylic acid and abbreviated GMP, is a nucleotide that is found in RNA. It is an ester of phosphoric acid with the nucleoside guanosine. ... Cytidine monophosphate, also known as 5-cytidylic acid and abbreviated CMP, is a nucleotide that is found in RNA. It is an ester of phosphoric acid with the nucleoside cytidine. ... Adenosine diphosphate, abbreviated ADP, is a nucleotide. ... Uridine diphosphate, abbreviated UDP, is a nucleotide. ... Cytidine diphosphate, abbreviated CDP, is a nucleotide. ... Jump to: navigation, search Adenosine triphosphate (ATP) is the nucleotide known in biochemistry as the molecular currency of intracellular energy transfer; that is, ATP is able to store and transport chemical energy within cells. ... Guanosine triphosphate (GTP) is also known as guanosine-5-triphosphate and G3P. Biochemically, GTP is 9-ÃŸ-D-ribofuranosylguanine-5-triphosphate or, equivalently, 9-ÃŸ-D-ribofuranosyl-2-amino-6-oxo-purine-5-triphosphate. ... Structure of cAMP Cyclic adenosine monophosphate (cAMP, cyclic AMP or 3-5-cyclic adenosine monophosphate) is a molecule that is important in many biological processes; it is derived from adenosine triphosphate (ATP). ... Cyclic guanosine monophosphate (cGMP) is a second messenger derived from GTP. Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). ... A nucleotide is a monomer or the structural unit of nucleotide chains forming nucleic acids as RNA and DNA. A nucleotide consists of a heterocyclic nucleobase, a pentose sugar, and a phosphate or polyphosphate group. ... Thymidine monophosphate, also known as 5-thymidylic acid and abbreviated TMP, is a nucleotide that is found in RNA. It is an ester of phosphoric acid with the nucleoside thymidine. ... Cytidine is a molecule (known as a nucleoside) that is formed when cytosine is attached to a ribose ring (also known as a ribofuranose) via a β-N1-glycosidic bond. ... Thymidine diphosphate, abbreviated TDP, is a nucleotide. ... A nucleic acid is a complex, high-molecular-weight biochemical macromolecule composed of nucleotide chains that convey genetic information. ... Jump to: navigation, search Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and many viruses). ... A locked nucleic acid (LNA) is a modified RNA nucleotide. ... PNA is peptide nucleic acid, a chemical similar to DNA or RNA but differing in the composition of its backbone. ... Jump to: navigation, search The life cycle of an mRNA in a eukaryotic cell. ... A non-coding RNA (ncRNA) is any RNA molecule that functions without being translated into a protein. ... The title given to this article is incorrect due to technical limitations. ... A non-coding RNA (ncRNA) is any RNA molecule that functions without being translated into a protein. ... Small interfering RNA (siRNA), sometimes known as short interfering RNA, are a class of 20-25 nucleotide-long RNA molecules that interfere with the expression of genes. ... Transfer RNA (abbreviated tRNA) is a small RNA chain (74-93 nucleotides) that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. ... Mitochondrial DNA (mtDNA, or less popularly, mDNA) is DNA which is not located in the nucleus of the cell but in the mitochondria. ... Oligonucleotides are short sequences of nucleotides (RNA or DNA), typically with twenty or fewer base pairs. ...

Contents

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