📋 CARBOHYDRATE STRUCTURES · COPYABLE DIAGRAMS
Fischer projections · Haworth rings · Glycosidic bonds · Polysaccharides · All text‑based & SVG (select, copy, paste)
01ALDOHEXOSES & KETOHEXOSES – Fischer & Haworth (copyable)
D-Glucose (Aldohexose)
C₆H₁₂O₆ · [α] +52.7° (equilibrium)
CHO
|
H—C—OH
|
HO—C—H
|
H—C—OH
|
H—C—OH
|
CH₂OH
Fischer projection (open chain)
α-D-glucopyranose β-D-glucopyranose
CH₂OH CH₂OH
| |
O C OH O C OH
\ | / \ | /
\ | / \ | /
C OH C OH
/| \ /| \
/ | \ / | \
O | OH O | OH
| |
OH OH
(OH at C1 down) (OH at C1 up)
Haworth pyranose forms · anomers α (OH axial down) / β (OH equatorial up)
D-Fructose (Ketohexose)
C₆H₁₂O₆ · sweetest natural sugar
CH₂OH
|
C=O
|
HO—C—H
|
H—C—OH
|
H—C—OH
|
CH₂OH
β-D-fructofuranose (5‑membered ring)
CH₂OH
|
O C
\ | \
\ | CH₂OH
C
/| \
/ | \
O | OH
|
OH
Furanose ring (fructofuranose) · ketone at C2
D-Galactose (C4 epimer of glucose)
C₆H₁₂O₆ · lactose component
CHO
|
H—C—OH
|
HO—C—H
|
HO—C—H ← OH on left at C4 (difference from glucose)
|
H—C—OH
|
CH₂OH
Epimer at carbon 4 → different spatial arrangement
02PENTOSES · DEOXYRIBOSE · AMINO SUGARS
D-Ribose (RNA)
C₅H₁₀O₅
CHO
|
H—C—OH
|
H—C—OH
|
H—C—OH
|
CH₂OH
2-Deoxy-D-ribose (DNA)
C₅H₁₀O₄
CHO
|
H—C—H ← missing –OH at C2
|
H—C—OH
|
H—C—OH
|
CH₂OH
Glucosamine & N-Acetylglucosamine
Glucosamine: N-Acetylglucosamine (GlcNAc):
CHO CHO
| |
H—C—NH₂ H—C—NH—COCH₃
| |
HO—C—H HO—C—H
| |
H—C—OH H—C—OH
| |
H—C—OH H—C—OH
| |
CH₂OH CH₂OH
Amino group at C2 → chitin, glycoproteins, cartilage
03DISACCHARIDES – Glycosidic bonds & reducing ends
Maltose · α(1→4)
C₁₂H₂₂O₁₁ · reducing sugar
Maltose = α-D-Glcp-(1→4)-α-D-Glcp
(Glucose₁) α1→4 (Glucose₂)
Lactose · β(1→4)
C₁₂H₂₂O₁₁ · milk sugar
Lactose = β-D-Galp-(1→4)-α-D-Glcp
Galactose (β) → Glucose (α)
Cleaved by lactase → glucose + galactose
Sucrose · α(1↔2)β · NON-REDUCING
C₁₂H₂₂O₁₁ · table sugar
Sucrose = α-D-Glcp-(1↔2)-β-D-Fruf
Both anomeric carbons linked → no free aldehyde/ketone
Hydrolysis: Sucrose + H₂O → Glucose + Fructose (invert sugar)
04POLYSACCHARIDES · STARCH · GLYCOGEN · CELLULOSE · CHITIN
Amylose (starch) · α(1→4) helix
Glc —α1→4— Glc —α1→4— Glc —α1→4— Glc —α1→4— Glc
(unbranched, helical, iodine deep blue)
Amylopectin (branched starch)
┌── Glc (α1→6 branch point)
Glc—Glc—Glc—Glc—Glc—Glc—Glc
│
└── Glc—Glc—Glc
(Branches every 24-30 residues via α1→6)
Glycogen (animal starch)
┌── Glc
Glc—Glc—Glc—Glc—Glc
│ └── Glc—Glc
└── Glc—Glc
(branches every 8–12 glucose units)
Highly compact → rapid energy release
Cellulose · β(1→4) linear fibrils
Glc—β1→4—Glc—β1→4—Glc—β1→4—Glc
(each glucose rotated 180°, extensive H‑bonds)
Indigestible by humans (no cellulase)
Chitin · β(1→4) N-acetylglucosamine
GlcNAc—β1→4—GlcNAc—β1→4—GlcNAc
(structural exoskeleton, fungal cell walls)
05STEREOCHEMISTRY · ANOMERS · EPIMERS · REDUCING SUGARS
α / β anomers of D-glucose
α-D-glucopyranose: OH at C1 is DOWN (axial) [α] +112°
β-D-glucopyranose: OH at C1 is UP (equatorial) [α] +18.7°
Equilibrium mixture: 36% α, 64% β → [α] +52.7° (mutarotation)
Common epimers of glucose
Glucose (C2 OH right, C4 OH right)
Mannose (C2 epimer: OH at C2 left)
Galactose (C4 epimer: OH at C4 left)
Reducing vs Non‑reducing sugars
REDUCING: free anomeric carbon (aldehyde or α‑hydroxyketone)
→ positive Benedict's / Fehling's test
Examples: Glucose, Fructose, Maltose, Lactose, Galactose
NON-REDUCING: both anomeric carbons involved in glycosidic bond
Examples: Sucrose, Trehalose
06METABOLIC PATHWAYS · VITAMIN C · CLINICAL
Aerobic glucose oxidation
C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + ~30–32 ATP
Glycolysis (2 ATP + 2 NADH)
Pyruvate → Acetyl-CoA (2 NADH)
TCA cycle (2 ATP + 6 NADH + 2 FADH₂)
Oxidative phosphorylation: 1 NADH ≈ 2.5 ATP, 1 FADH₂ ≈ 1.5 ATP
L-Ascorbic acid (Vitamin C)
O=C
/ \
HO-C C-OH
| |
HO-C C=O
\ /
C—OH
|
CH₂OH
(C₆H₈O₆ · carbohydrate-derived lactone)
Antioxidant · Collagen hydroxylation · Prevents scurvy
Sucrose inversion · Optical rotation
Sucrose [α] +66.5° → Hydrolysis → Glucose (+52.7°) + Fructose (–92°)
Net rotation: –20° (levorotatory) → "Invert sugar"
07GLYCOCALYX · BLOOD GROUP ANTIGENS · RECOGNITION
ABO blood group determinants
Type O: H antigen (Fucose α1→2 Gal)
Type A: H antigen + N‑acetylgalactosamine (GalNAc) α1→3 Gal
Type B: H antigen + D‑Galactose α1→3 Gal
Terminal sugar residues define blood type compatibility
Glycocalyx (cell coat)
Plasma membrane → glycolipids & glycoproteins
Oligosaccharide chains → cell adhesion, immune recognition, protection
Example: Selectins bind to sialyl Lewis X antigen
Clinical correlations
Lactose intolerance: lactase deficiency → bloating/diarrhea
Diabetes mellitus: hyperglycemia, HbA1c test
Glycogen storage disease: von Gierke (G6Pase deficiency)
Scurvy: vitamin C deficiency → impaired collagen
08SUGAR DERIVATIVES · URONIC ACIDS · ALDITOLS · DEOXY SUGARS
Uronic acids (Glucuronic acid)
Oxidation at C6: –CH₂OH → –COOH
D-Glucuronic acid: key for detoxification (glucuronidation), GAG component
Alditols (sugar alcohols)
Glucose → Sorbitol (used in sugar-free products)
Xylose → Xylitol (anticariogenic sweetener)
Mannose → Mannitol (diuretic, osmotic agent)
Deoxy sugars & rare sugars
L-Fucose (6-deoxy-L-galactose): blood group antigens
L-Rhamnose (6-deoxy-L-mannose): plant polysaccharides
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