Polysaccharides: Cellulose and Glycogen; Importance
Structures and biological roles of cellulose and glycogen, highlighting their differences from starch, and overall importance of carbohydrates.
What is Polysaccharides: Cellulose and Glycogen; Importance?
A complex carbohydrate composed of long chains of monosaccharide units linked together by glycosidic bonds.
Key points
- Differentiate between cellulose and glycogen based on their structure.
- Explain the functional significance of the structural differences between cellulose and glycogen.
- Identify the biological roles of cellulose and glycogen in plants and animals, respectively.
- Understand the importance of polysaccharides as a class of biomolecules.
Common exam trap
Confusing the linkages in cellulose (β-1,4) and glycogen (α-1,4 and α-1,6).
Definitions
- Term
Polysaccharide
- Meaning
A complex carbohydrate composed of long chains of monosaccharide units linked together by glycosidic bonds.
- Term
Glycosidic bond
- Meaning
A type of covalent bond that links a carbohydrate molecule to another group, typically another carbohydrate.
- Term
Cellulose
- Meaning
A structural polysaccharide found in the cell walls of plants, made of β-D-glucose units linked by β-1,4 glycosidic bonds.
- Term
Glycogen
- Meaning
A storage polysaccharide found in animals, primarily in the liver and muscles, made of α-D-glucose units linked by α-1,4 and α-1,6 glycosidic bonds.
Learning objectives
Differentiate between cellulose and glycogen based on their structure.
Explain the functional significance of the structural differences between cellulose and glycogen.
Identify the biological roles of cellulose and glycogen in plants and animals, respectively.
Understand the importance of polysaccharides as a class of biomolecules.
Prerequisites
Monosaccharides (glucose)
Glycosidic bonds
Polymerization
Common mistakes
Confusing the linkages in cellulose (β-1,4) and glycogen (α-1,4 and α-1,6).
Assuming glycogen is only found in the liver.
Not differentiating between structural (cellulose) and storage (glycogen) roles.
Equating the digestibility of cellulose with that of starch or glycogen.
Keywords
Polysaccharide
Carbohydrate
Cellulose
Glycogen
Glycosidic bond
β-1,4 linkage
α-1,4 linkage
α-1,6 linkage
Plant cell wall
Animal storage
Structural polysaccharide
Storage polysaccharide
Practice preview
Which of the following is a structural polysaccharide found in plant cell walls?…
easy
The β-1,4 glycosidic linkages in cellulose allow for the formation of:…
medium
Glycogen serves as a reserve food material in which of the following organisms?…
easy