Energy metabolism: essential components of nucleic acids (dna and rna) Structure: combine 2 organic chemical functional groups: Aldehyde: bonded to 1 other carbon and 1 hydrogen. Therefore sugars are polyhydroxy aldehydes or polyhydroxy ketones: ketoses: ketone sugars, aldoses: aldose sugars aldehyde. Poorly soluble in organic solvents (ether, hexane: hydrophilic, polar, colourless, standard formula: (ch2o)n. 3 c atoms: 1 carbonyl group, 2 cs bearing hydroxyl groups: hexoses are the most common monosaccharides in nature. Asymmetry or handedness: needs to have 4 different constituents (cannot superimpose) Enantiomers: mirror images (left handed or right handed, have identical chemical properties, have different optical activity. Plane of polarization when polarized light is passed through each is bent in different directions. Stereoisomers that differ in handedness at some c atoms but not others: do not have identical chemical properties. 2n n = number of chiral centres: e. g.