JEE Main & Advanced Chemistry Biomolecules / जैव-अणु Monosaccharides

These are the simplest one unit non-hydrolysable sugars. They have the general formula \[{{C}_{n}}{{H}_{2n}}{{O}_{n}}\] where  n varies from 3 to 9 carbon atoms. About 20 monosaccharides occur in nature. The simplest are trioses (n=3)

\[\underset{\text{Triose}}{\mathop{{{C}_{3}}{{H}_{6}}{{O}_{3}}}}\,\,\,\,;\underset{\text{Glyceraldehyde}}{\mathop{\,\,\begin{matrix}    H-C=O\,\,  \\    |\,\,\,  \\    H-C-OH  \\    |\,\,\,\,  \\    \,\,\,\,\,\,\,\,\,\,C{{H}_{2}}OH  \\ \end{matrix}}}\,\,\,\,\,;\,\,\underset{\text{Dihydroxyacetone }}{\mathop{\begin{matrix}    C{{H}_{2}}OH\,  \\    |\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,  \\    C=O\,\,\,\,\,\,\,  \\    |\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,  \\    C{{H}_{2}}OH\,  \\ \end{matrix}}}\,\]                

The most important naturally occurring monosaccharides are pentoses and hexoses. A common pentose is ribose and two common hexoses are glucose and fructose.                

Except ketotriose {dihydroxyacetone}, all aldose and ketoses {monosaccharides} contain asymmetric carbon atoms and are optically active.