Ribose and deoxyribose are both organic compounds with biological significance. Although both these compounds are sugars, there are certain differences between the two. Here we shall look into their similarities and differences, based on the following parameters. ► Molecular Formula ► Structure ► Biological Importance The molecular formula of a compound gives us the idea about the elements that make up the particular compound, and the number of atoms of each element present in the compound. The molecular formula of ribose is C₅H₁₀O₅. The molecular formula of deoxyribose is C₅H₁₀O₄. Similarities ► Both the molecules have 5 carbon atoms and 10 hydrogen atoms. Differences While a molecule of ribose has 5 oxygen atoms, a molecule of deoxyribose has only 4 oxygen atoms. The chemical structures of both ribose and deoxyribose are given below. Looking at them, we can note the following points. Similarities ► Ribose and deoxyribose are both monosaccharides or simple sugars. ► Both are aldopentoses, which means both are pentose sugar molecules which, in their open chain form, have an aldehyde functional group at one end. A pentose sugar is one that is made up of 5 carbon atoms. The open chain forms of both are given below. Differences ► While ribose is a regular molecule of sugar, deoxyribose is a modified sugar. Deoxyribose is a deoxy sugar, which is derived from ribose by the loss of an oxygen atom. This is the reason the number of oxygen atoms in deoxyribose is one less than that in ribose. This difference makes it possible for enzymes to distinguish between the two sugar molecules. ► Ribose, like other aldopentoses, has three chiral centers, which makes it possible for ribose to have 8 different stereoisomers. 2-Deoxyribose, on the other hand, has two enantiomers (stereoisomers that are identical but non-superposable). Ribose and 2-deoxyribose are constituents of nucleic acids. Let's see the similarities and differences between the functions of the two, within the living cells. Similarities ► Both ribose and deoxyribose molecules undergo phosphorylation to form ribonucleotide and deoxyribonucleotide, respectively. These nucleotides are building blocks of nucleic acids, which carry the genetic information of living cells. Differences ► 2-Deoxyribose is a component of DNA (deoxyribonucleic acid). DNA is the molecule that encodes genetic information in living organisms. Here we see a deoxyribonucleotide which forms a monomer or single unit of the DNA molecule. It is composed of a deoxyribose sugar, a nitrogenous base, and one phosphate group. Ribose is a component of RNA (ribonucleic acid). RNA molecules play a key role in the coding, decoding, and regulation of genetic information. It also plays a key role in gene expression. Here we see a ribonucleotide which forms the single unit of the RNA molecule. It is composed of a ribose sugar, a phosphate group, and a nitrogenous base (purines or pyrimidines). So, we see that both ribose and deoxyribose are essential for our body. Ribose supplements are available in the market, but the intake of these can result in certain side effects.