Monosaccharides Although most plants contain quite few and minor amounts of free monosaccharides, they are the building blocks of all carbohydrates. Plant carbohydrates consist mostly of aldohexoses aldopentoses and 2-ketohexoses. In addition, derivatives of the basic monosaccharides occur to some extent, especially hexuronic acids and deoxyhexoses and –pentoses. In some cases, a monosaccharide unit may
