Deoxyribose

Deoxyribose is a sugar with the chemical formula C ₅ H ₁₀ O ₄ , derived from ribose by loss of an oxygen atom.

Summary

[ disguise ]

• 1 Description
  • 1 Physical properties
• 2 Origin
  • 1 Differences between DNA and RNA
• 3 Structure
• 4 Importance
• 5 External links
• 6 Sources

Description

Deoxyribose, or more precisely 2-deoxyribose, is a monosaccharide of five carbon atoms (pentose, with the empirical formula C ₅ H ₁₀ O ₄ , derived from ribose by loss of an oxygen atom in the 2′ hydroxyl, and by This does not correspond to the general formula of monosaccharides (CH ₂ O)n). It is part of the DNA.

Physical properties

It is a colorless crystalline solid, quite soluble in water . In its furanose form (pentagonal ring) it is part of the nucleotides that make up the chains of deoxyribonucleic acid (DNA).

Origin

In nature there are only two types of nucleic acids: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) and they are present in all cells.

Its biological function was not fully confirmed until Avery and his collaborators demonstrated in 1944 that DNA was the molecule that carries genetic information.

Nucleic acids have at least two functions: transmitting hereditary characteristics from one generation to the next and directing the synthesis of specific proteins.

Both the RNA molecule and the DNA molecule have a helical structure. Chemically, these acids are formed, as we said, by units called nucleotides: each nucleotide, in turn, is made up of three types of compounds:

1. A pentose or five-carbon sugar: there are two types of pentoses that are part of nucleotides, ribose and deoxyribose, the latter differs from the first because it lacks an oxygen and hence its name. DNA only has deoxyribose and RNA has only ribose, and their name, deoxyribonucleic acid and ribonucleic acid, has been derived from the pentose they carry, respectively.

2.A nitrogenous base: which are ringed compounds that contain nitrogen. Five of them can be identified: adenine, guanine, cytosine, uracil and thymine.

3.A phosphate radical: it is derived from phosphoric acid (H ₃ PO ₄ -). ANs are linear polymers in which the repeating unit, called the nucleotide (figure on the left), is made up of: (1) a pentose (ribose or deoxyribose), (2) phosphoric acid and (3) a nitrogenous base (purine or pyrimidine).

The union of pentose with a base constitutes a nucleoside. The union through an ester bond between the nucleoside and the phosphoric acid gives rise to the nucleotide.

The sequence of the nucleotides determines the code for each particular nucleic acid. In turn, this code tells the cell how to reproduce a duplicate of itself or the proteins it needs for its survival.

Differences between DNA and RNA

• The molecular weight of DNA is generally greater than that of RNA
• The sugar in RNA is ribose, and that in DNA is deoxyribose.
• RNA contains the nitrogenous base uracil, while DNA contains thymine.
• The spatial configuration of DNA is that of a double helical, while RNA is a linear polynucleotide, which may occasionally present intrastrand pairings.

Structure

Several isomers exist with the formula H-(C=O)-(CH ₂ )-(CHOH) ₃ -H, but in deoxyribose the hydroxyl groups are on the same side of the Fischer Projection. The term “2-deoxyribose” can equally refer to two enantiomers: the biologically important D-2-deoxyribose and its unusual mirror image L-2-deoxyribose.1 D-2-Deoxyribose is a precursor of the nucleic acid DNA. 2-Deoxyribose is an aldopentose, that is, a monosaccharide with five carbon atoms and containing an aldehyde functional group. In aqueous solution, deoxyribose consists primarily of a mixture of three structures: the linear form H-(C=O)-(CH ₂ )-(CHOH) _3- H and two variable cyclic forms, deoxyribofuranose, with a five-ring ring. carbon atoms, and deoxyribopyranose from a six ring. The second form is the predominant one.

Importance

As a component of DNA, 2-deoxyribose derivatives play an important role in biology. The DNA (deoxyribonucleic acid) molecule, which is the main source of genetic information in life, consists of a long chain of dexosyrribose-containing units called nucleotides, linked through phosphate groups. In standard nomenclature, a DNA nucleotide consists of a deoxyribose molecule with an organic base (usually adenine, thymine, guanine, or cytosine) attached to the 1′ carbon of the sugar. The 5′ hydroxyl of each deoxyribose unit is replaced by a phosphate (forming a nucleotide) that binds to the 3′ carbon of the deoxyribose previous in the chain. The backbones of DNA and RNA are structurally similar, although RNA is single-stranded and composed of ribose instead of deoxyribose. The absence of the 2′ hydroxyl in deoxyribose is apparently responsible for the increased mechanical flexibility of DNA compared to RNA, which allows it to assume the double helix conformation, and also (in eukaryotes) to be compactly coiled within the small cell nucleus. . Double helix DNA is generally much longer than RNA molecules. Other important biological derivatives of deoxyribose include mono-, di-, and triphosphates, as well as 3′-5′ cyclic monophosphates.