CHEM 53.10 - Polysaccharides

Glycans

Other term for polysaccharides

False

T or F: A monosaccharide can form a glycosidic bond with another monosaccharide even without a free anomeric carbon

True

T or F: If neither monosaccharide has a free anomeric carbon (e.g., both are involved in glycosidic bonds already), a new glycosidic bond cannot be formed.

Anomeric carbon, hydroxyl

Polysaccharides are connected through a glycosidic bond between the ___ atom of one residue and the ___ group of the next

False

T or F: Hydrogen bonding is the primary structural linkage in polysaccharides

Homopolysaccharides

Type of polysaccharide that consists of repeating units of the same sugar

Heteropolysaccharides

Type of polysaccharide that contains mix of different sugar units with specialized roles

Length, branching

Polysaccharides can vary in ____ or amount of ___

False

T or F: One sugar residue can form more than one glycosidic bond

D-glucose

Most common constituent in glycans

True

T or F: Monosaccharide derivatives can also constitute polysaccharides

Energy, structural

Polysaccharides can help store ___ and provide ___ support

Starch, glycogen

Two of the major energy-storing polysaccharides

Homoglycans, glucose

Starch and glycogen are ___ (homo/heteroglycans) which are composed of ___ (what monosaccharide residue)

Starch

Polysaccharide that is the principle energy reserve in plants

starch

polysaccharide used for energy storage in plants

α(1→4) glycosidic bonds

type of bond linking glucose residues in α-amylose

several thousand residues

length that α-amylose chains can stretch

α(1→4) glycosidic bonds

type of bond mainly linking glucose residues in amylopectin

α(1→6) linkage

type of bond responsible for branching in amylopectin

24 to 30 residues

average frequency of branching in amylopectin

linear

structure of α-amylose

branched

structure of amylopectin

α-glycosidic bonds

allow α-amylose to adopt a helically coiled conformation

irregular aggregation

characteristic of helically coiled α-amylose structure

True

T or F: Amylose adopts a helical conformation in water.

True

T or F: The iodine test produces a blue color in the presence of starch.

False

T or F: Starch digestion in animals begins in the small intestine.

True

T or F: α-glucosidase removes one glucose unit at a time in the small intestines for absorption.

Amylose in water

adopts a helical conformation, enabling I₂ to insert and produce a blue color (basis for iodine test)

Starch digestion

begins with salivary amylase hydrolyzing α(1→4) linkages, followed by α-glucosidase in the intestines releasing glucose units