Q.88 The primary difference between glycogen and cellulose is in the
(A)types of constituent monosaccharides
(B)number of monomers per molecule
(C)configuration of the monomers
(D)susceptibility to acid hydrolysis
Glycogen and cellulose are both glucose polymers, but their primary structural difference lies in glycosidic bond configuration: glycogen uses α-1,4 and α-1,6 linkages (branched, helical), while cellulose uses β-1,4 linkages (linear, rigid). The correct answer is (C) configuration of the monomers.
Correct Answer
(C) Configuration of the monomers
Structural Comparison
Both polysaccharides consist of D-glucose monomers linked via glycosidic bonds, but configuration (α vs β anomeric carbon orientation) determines properties:
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Glycogen: α-D-glucose; α-1,4 (linear chains), α-1,6 (branches every 8-12 residues); compact, soluble, rapidly hydrolyzable by glycogen phosphorylase.
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Cellulose: β-D-glucose; β-1,4 only; straight chains form H-bonded microfibrils; insoluble, structural rigidity in plant cell walls.
This dictates function: energy storage (glycogen) vs structural support (cellulose).
Option Analysis
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(A) Types of constituent monosaccharides: Wrong. Both use D-glucose exclusively.
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(B) Number of monomers per molecule: Wrong. Both highly polymeric (10³-10⁷ glucose units); difference is architectural, not absolute count.
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(C) Configuration of the monomers: Correct. α (glycogen) vs β (cellulose) linkages create branched/helix vs linear/fibrous forms.
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(D) Susceptibility to acid hydrolysis: Wrong. Secondary effect of structure; both hydrolyzable but cellulose more resistant due to crystallinity.
Introduction to Glycogen Cellulose Difference
Glycogen cellulose primary difference configuration defines GATE Life Sciences biochemistry Q.88: both glucose polymers differ fundamentally in α vs β glycosidic linkages (C), yielding branched energy storage vs linear structural roles. Monomer type/quantity identical.
Key Structural Distinctions
| Feature | Glycogen | Cellulose |
|---|---|---|
| Monomer | α-D-glucose | β-D-glucose |
| Linkages | α-1,4 & α-1,6 (branched) | β-1,4 (linear) |
| Structure | Helical, compact | Straight microfibrils |
| Function | Energy reserve (liver/muscle) | Cell wall support |
| Digestibility | Amylase-accessible | Cellulase-only |
Configuration drives H-bonding/digestibility.
Q.88 Why Configuration (C)?
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A: Both D-glucose → wrong.
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B: Both massive polymers → wrong.
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C: α-branching vs β-linearity → correct primary difference.
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D: Hydrolysis resistance = consequence, not cause.
Answer: (C)—anomeric configuration fundamental.
Functional Consequences
Glycogen: Branching → Multiple phosphorylase ends → Rapid mobilization
Cellulose: β-1,4 → Anti-parallel chains → Extensive H-bonding → Tensile strength
Humans lack β-glucosidase → dietary fiber.
GATE Biochemistry Tips
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Mnemonic: “α = Animal storage (Glycogen), β = Botanic structure (Cellulose).”
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Compare: Starch (plant glycogen analog, α-linkages).
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High-yield: Glycosidic bond type dictates enzyme specificity.
Master glycogen cellulose primary difference configuration for perfect carbohydrate structure questions.
