Chapter 26, Problem 26.68P

Interpretation Introduction

(a)

Interpretation:

It is to be identified and classified each glycosidic linkage in a given portion of the polysaccharide of an arabinoxylan.

Concept introduction:

The glycoside linkage is part of an acetal function group, in which a carbon atom is attached to the two alkoxy groups (OR). The polysaccharide which is used to store energy is called a storage polysaccharide e.g. starch and glycogen and other polysaccharide are responsible for maintaining the structure of the organism are called structural polysaccharide e.g. cellulose. In a six-membered ring sugar, when the bond between the acetal carbon and OR is axial is characterized as $\text{α }$ configuration and when that bond on equatorial are characterized as $\text{ β}$ configuration. In a five-membered ring sugar, the analogous configuration for $\text{α }$ is for the acetal bond on the side of the ring opposite the carbon-containing substituent (i.e. ${\text{CH}}_{\text{2}}\text{OH}$) and that is $\text{ β}$ configuration when those on the same side of the ring.

Interpretation Introduction

(b)

Interpretation:

It is to be explained arabinoxylan functions as a storage polysaccharide or a structural polysaccharide on the basis of its structure.

Concept introduction:

The glycoside linkage is part of an acetal function group, in which a carbon atom is attached to the two alkoxy groups (OR). The polysaccharide which is used to store energy is called a storage polysaccharide e.g. starch and glycogen and other polysaccharide are responsible for maintaining the structure of the organism are called structural polysaccharide e.g. cellulose. In a six-membered ring sugar, when the bond between the acetal carbon and OR is axial is characterized as $\text{α }$ configuration and when that bond on equatorial are characterized as $\text{ β}$ configuration. In a five-membered ring sugar, the analogous configuration for $\text{α }$ is for the acetal bond on the side of the ring opposite the carbon-containing substituent (i.e. ${\text{CH}}_{\text{2}}\text{OH}$) and that is $\text{ β}$ configuration when those on the same side of the ring.