All those compounds which can be chemically
correlated to D (+) isomer of glyceraldehyde are said to have D-
configuration whereas those which can be correlated to ‘L’ (–) isomer of
glyceraldehyde are said to have L—configuration In L (–) isomer –OH
group is on left hand side as you can see in the structure For assigning
Rationalised 2023-24
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Biomolecules
the configuration of monosaccharides, it is the lowest asymmetric carbon
atom (as shown below) which is compared As in (+)   glucose, —OH on
the lowest asymmetric carbon is on the right side which is comparable
to (+) glyceraldehyde, so (+) glucose is assigned D-configuration