Question

Drawthe structure of:

(a) a polysaccharide formed by joining d-mannose units in $\mathbf{1}\mathbf{\to }\mathbf{4}\mathbf{-}\mathbf{\beta }$-glycosidic linkages;

(b) a polysaccharide formed by joining d-glucose units in $\mathbf{1}\mathbf{\to }\mathbf{6}\mathbf{-}\mathbf{\alpha }$-glycosidic linkages.

The polysaccharide in (b) is dextran, a component of dental plaque.

Short answer

Answer

Galactomannan

Dextran

Step-by-step solution

Galactomannan

The carbohydrate galactomannan is an example of a polysaccharide of one of the epimers of glucose, that is, mannose. In this polysaccharide, mannose is connected by -$\mathbf{1}\mathbf{\to }\mathbf{4}\mathbf{-}\mathbf{\beta }$glycosidic linkage.

Dextran

The biopolymer dextran produced by bacteria consists of the monosaccharide unit glucose.It is present in wine. It is used in the medicinal field and helps to restore blood plasma. It is also present in dental plaque.

Structures

(a) The structure of the polysaccharide unit formed by joining d-mannose units in $1\to 4-\mathrm{\beta }$-glycosidic linkages is Galactomannan.

Galactomannan

(b) A polysaccharide formed by joining d-glucose units in $1\to 6-\mathrm{\alpha }$-glycosidic linkages is Dextran.

Dextran