📌 Definition & Classification
🖇 Polysaccharides = Carbohydrates with >10 monosaccharide units linked by O-glycosidic bonds.
🟠 Main functions: Storage + Structural support.
🟣 Types:

Homopolysaccharides → same monosaccharide units.
Heteropolysaccharides → different monosaccharide units.

📌 Homopolysaccharides (Glucosans & Fructosans)
🟣 Glucosans → made of D-glucose units.
🟣 Fructosans → made of D-fructose units.

🖇 A. Glucosans Types

📌 1. Starch (Plant Storage Form)

Composed of Amylose (15–20%) + Amylopectin (80–85%).
Amylose: Linear chain, α-1,4 bonds, water-soluble, forms helix.
Amylopectin: Branched chain, α-1,4 + α-1,6 linkages (every 24–30 units), water-insoluble.
Hydrolysis: by α-amylase / HCl → dextrins → maltose.

🚨 Clinical Importance:

Main dietary carbohydrate source.
Digestion begins in mouth → salivary amylase.

📌 2. Glycogen (Animal Storage Form)

Similar to amylopectin but more branched (every 8–12 glucose units).
Stored mainly in liver & muscles.

🟣 Functions:

Liver glycogen: maintains blood glucose (10–18 hrs fasting).
Muscle glycogen: provides energy for muscle contraction.

🚨 Clinical Importance:

Rapid glucose release due to high branching → vital for energy demand.

📌 3. Dextrins

Hydrolytic products of starch (by amylase).
Sequence: Starch → Amylodextrin → Erythrodextrin → Achrodextrin → Maltose.
Used in: infant feeding.

📌 4. Dextrans

Synthetic, branched glucose polymers.
Bonds: α-1,3 and α-1,6 (at branches).
Produced by oral bacteria → form dental plaque.
Medical use: plasma substitute (in shock therapy).

📌 5. Cellulose (Structural Polysaccharide)

Linear chain of β-glucose units (β-1,4 linkages).
Insoluble in water, non-digestible by humans (no β-1,4 enzyme).
Main plant structural material.

🚨 Clinical Importance:

Major component of dietary fiber → essential for digestive health.

🖇 B. Dietary Fiber
🟣 Components: Cellulose, Pentosans, Gums, Pectin, Lignin.
🟠 Types:

Soluble fiber (e.g., gums in fruits, oats) → dissolves in water.
Insoluble fiber (e.g., cellulose in vegetables, wheat) → doesn’t dissolve.

🚨 Clinical Importance:

↓ Colon cancer risk (absorbs toxins, fermented → anti-cancer fatty acids).
↓ Blood cholesterol (binds bile acids & cholesterol).
↓ Cardiovascular risk (inverse relation with MI & stroke).
↓ Blood glucose spikes (delays gastric emptying).
Prevents constipation (absorbs water → bulky stool).
Helps weight loss (↑ satiety).
Relieves IBS symptoms.

📌 B. Fructosans: Inulin

Found in plants (e.g., artichoke roots).
Made of fructose units (β-1,2 linkages).
Not digestible by human enzymes.

🚨 Clinical Importance:

Used for renal function tests (inulin clearance).

Biochemistry