Which Is the Most Abundant Polysaccharide? | Biology MCQ

Biology MCQ:

_______ is the most abundant polysaccharide on Earth.

A. Glycogen
B. Starch
C. Cellulose
D. Chitin

✅ Correct Answer: C. Cellulose

Explanation

Cellulose is the most abundant naturally occurring polysaccharide. It is a structural carbohydrate made of long chains of β-D-glucose units joined by β(1→4) glycosidic bonds.

It is the main component of plant cell walls, where it provides strength and rigidity. The large amount of cellulose present in plant biomass makes it one of the most abundant organic polymers in the biosphere.

Cellulose, Starch, Glycogen & Chitin

Key Difference

The important distinction is their function and structure:

• Cellulose: structural polysaccharide
• Starch: plant storage polysaccharide
• Glycogen: animal storage polysaccharide
• Chitin: structural polysaccharide containing nitrogen

Why Can't Humans Digest Cellulose?

Humans do not produce cellulase, the enzyme required to break the β(1→4) bonds of cellulose. Consequently, it passes through the digestive system largely undigested and contributes to dietary fiber.

Some microorganisms can produce cellulase. This is particularly important in herbivorous animals, where microbial digestion helps make nutrients from plant material available.

Exam Point 📝

Question: Which is the most abundant polysaccharide in nature?

Answer: Cellulose ✅

🧠 Remember:
Cellulose → Plant cell wall → Structural support

Frequently Asked Questions

What is cellulose?
Cellulose is a polysaccharide composed of β-D-glucose units and is a major component of plant cell walls.

Where is cellulose found?
It is primarily found in plant cell walls.

Why is cellulose important?
It gives plants structural strength and contributes to the rigidity of their tissues.

Can humans digest cellulose?
No. Humans lack the enzyme cellulase needed to digest it efficiently.

Is cellulose a carbohydrate?
Yes. It is a complex carbohydrate belonging to the polysaccharide group.

 Revision Points

🔹 Most abundant polysaccharide: Cellulose
🔹 Monomer: β-D-glucose
🔹 Bond: β(1→4) glycosidic bond
🔹 Location: Plant cell wall
🔹 Function: Structural support
🔹 Human digestion: Not digested; dietary fiber

Final Answer

✅ C. Cellulose

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