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RNA is transcribed with only four bases (adenine, cytosine, guanine and uracil), [19] but these bases and attached sugars can be modified in numerous ways as the RNAs mature. Pseudouridine (Ψ), in which the linkage between uracil and ribose is changed from a C–N bond to a C–C bond, and ribothymidine (T) are found in various places (the ...
Nucleic acids RNA (left) and DNA (right). Nucleic acids are large biomolecules that are crucial in all cells and viruses. [1] They are composed of nucleotides, which are the monomer components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid ...
The purine nitrogenous bases are characterized by their single amino group (−NH 2), at the C6 carbon in adenine and C2 in guanine. [5] Similarly, the simple-ring structure of cytosine, uracil, and thymine is derived of pyrimidine, so those three bases are called the pyrimidine bases. [6] Each of the base pairs in a typical double-helix DNA ...
Each group of three bases, called a codon, corresponds to a single amino acid, and there is a specific genetic code by which each possible combination of three bases corresponds to a specific amino acid. The central dogma of molecular biology outlines the mechanism by which proteins are constructed using information contained in nucleic acids.
At neutral pH, nucleic acids are highly charged as each phosphate group carries a negative charge. [7] Both DNA and RNA are built from nucleoside phosphates, also known as mononucleotide monomers, which are thermodynamically less likely to combine than amino acids. Phosphodiester bonds, when hydrolyzed, release a considerable amount of free energy.
A tetraloop is a four-base pairs hairpin RNA structure. There are three common families of tetraloop in ribosomal RNA: UNCG, GNRA, and CUUG (N is one of the four nucleotides and R is a purine). UNCG is the most stable tetraloop. [9] Pseudoknot is an RNA secondary structure first identified in turnip yellow mosaic virus. [10]
This RNA copy is then decoded by a ribosome that reads the RNA sequence by base-pairing the messenger RNA to transfer RNA, which carries amino acids. Since there are 4 bases in 3-letter combinations, there are 64 possible codons (4 3 combinations). These encode the twenty standard amino acids, giving most amino acids more than one possible ...
C 4 H 4 N 2 O 2 → H 3 NCH 2 CH 2 COO − + NH + 4 + CO 2. Oxidative degradation of uracil produces urea and maleic acid in the presence of H 2 O 2 and Fe 2+ or in the presence of diatomic oxygen and Fe 2+. Uracil is a weak acid. The first site of ionization of uracil is not known. [12] The negative charge is placed on the oxygen anion and ...