CHEMISTRY GLOSSARY

nucleotide    →   nukleotid

Nucleotides are the components that made up nucleic acids. They have three major components: the first component is a nitrogenous base, which is derivative of one of two parent compounds, pyrimidine or purine; the second is a pentose, or five carbon sugar group; the third is a unit of phosphate. Each group of three nucleotides in a gene is known as a codon. Whenever the phosphate group is not present, a nucleotide becomes a nucleoside.

adenosine triphosphate    →   adenozin trifosfat

Adenosine triphosphate (ATP) is nucleotide that is of fundamental importance as a carrier of chemical energy in all living organisms. It consists of adenin linked to D-ribose).

deoxyribonucleic acid    →   dezoksiribonukleinska kiselina

Deoxyribonucleic acid (DNA) is a nucleic acid with 2-deoxy-D-ribose as the sugar in its nucleotides. DNA contains encoded genetic information, specifically templates for the synthesis of all of an organism’s proteins and enzymes.

DNA was first identified in the 1869 by Swiss chemist Friedrich Miescher (1844-1895). In 1953, American biologist James Dewey Watson (1928-) and English physicist Francis Harry Compton Crick (1916–2004) had discovered that DNA occurs in the cell as a double helix, with two long strands of the molecule wound around each other, and further that the chemical structure of the molecule dictates that adenine (A) always aligns or pairs with thymine (T), and cytosine (C) always pairs with guanine (G). It is this base pairing that allows DNA in a cell to copy itself, and transfer its information to a new cell. The diameter of the helix is 2.0 nm and there is a residue on each chain every 0.34 nm in the z direction. The angle between each residue on the same strand is 36°, so that the structure repeats after 10 residues (3.4 nm) on each strand.

nucleic acid    →   nukleinska kiselina

Nucleic acids are a complex, high-molecular-weight biochemical macromolecules composed of nucleotide chains that convey genetic information. The most common nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Each nucleic acid chain is composed of subunits called nucleotides, each containing a sugar, a phosphate group, and nitrogenous base. DNA was first discovered in 1869 by the Swiss biochemist Friedrich Miescher (1844-1895).

Both DNA and RNA contain the two major purine bases adenine (A) and guanine (G) and one of the major pyrimidines, cytosine (C). Of the other two pyrimidines, thymine (T) is found in DNA and uracil (U) is found in RNA. There are two major pentoses in nucleic acids:2'-deoxy-D-ribose in DNA and D-ribose in RNA.

Nucleotides are linked together in both DNA and RNA in a polymeric fashion via covalent bonds. These bonds exist through phosphate-group bridges in which the 5' hydroxyl group of one nucleotide unit is joined to the 3' hydroxyl group of the next nucleotide. RNA is usually a single-stranded molecule, whereas DNA is usually double-stranded.

ribonucleic acid    →   ribonukleinska kiselina

Ribonucleic acid is a complex organic compound in living cells that is concerned with protein synthesis. Plays an intermediary role in converting the information contained in DNA into proteins. RNA carries the genetic information from DNA to those parts of the cell where proteins are made. Some viruses store their genetic information as RNA not as DNA.

Ribonucleic acid is a similar molecule to DNA but with a slightly different structure.

The structural difference with DNA is that RNA contains a -OH group both at the 2' and 3' position of the ribose ring, whereas DNA (which stands, in fact, for deoxy-RNA) lacks such a hydroxy group at the 2' position of the ribose. The same bases can be attached to the ribose group in RNA as occur in DNA, with the exception that in RNA thymine does not occur, and is replaced by uracil, which has an H-group instead of a methyl group at the C-5 position of the pyrimidine. Unlike the double-stranded DNA molecule, RNA is a single-stranded molecule.

The three main functionally distinct varieties of RNA molecules are: (1) messenger RNA (mRNA) which is involved in the transmission of DNA information, (2) ribosomal RNa (rRNA) which makes up the physical machinery of the synthetic process, and (3) transfer RNA (tRNA) which also constitutes another functional part of the machinery of protein synthesis.