Carbs
On this page 2 sections
Sugars
Non-Reducing Sugar:
◦ Sucrose (Table sugar — composed of Glucose + Fructose linked by an alpha-1,2-glycosidic bond). Both anomeric carbons are involved in the bond, leaving no free aldehyde or ketone group to reduce Fehling's or Benedict's reagent.
◦ Trehalose is another common non-reducing disaccharide.
Reducing Sugars (Have a free anomeric carbon):
◦ All Monosaccharides (Glucose, Fructose, Galactose, Ribose, etc.)
◦ Reducing Disaccharides: Lactose (Milk sugar) and Maltose (Malt sugar)
• Monosaccharides: ALWAYS Reducing.
• Disaccharides: Maltose & Lactose are Reducing; Sucrose is NON-reducing.
Polysaccharides
| Polysaccharide | Monomer (Sugar Unit) | Enzyme Responsible | Substrate Used | Linkage Type | Major Clinical / MCQ Significance |
| Dextran | Glucose (Glucan) | Glucosyltransferase (Dextransucrase) | Sucrose | alpha {-1,6} (main) alpha {-1,3} (branches) | • Synthesized by Streptococcus mutans • Essential for bacterial adhesion to enamel (dental plaque formation) |
| Levan (Fructan) | Fructose (Fructan) | Levansucrase (Fructosyltransferase) | Sucrose | beta {-2,6} | • Synthesized by oral bacteria • Serves as an extracellular nutrient reserve in dental plaque |
| Inulin | Fructose (Fructan) | Plant enzymes (not bacterial) | Plant sugars | beta {-2,1} | • Plant storage polysaccharide • Gold standard for measuring Glomerular Filtration Rate (GFR) |
