BIBC 120 Lecture Notes - Anomer, Carbohydrate, Galactose
24 May 2018
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Week 3.1
CARBOHYDRATES
1) Macronutrient Calories per Gram
- Carbohydrates yield 4 kcal/gram
i. half of mass is from oxygen which doesn’t contribute to being oxidized
for heat energy → less energy provided per gram
- Protein (catabolism of amino acids) yields 4 kcal/gram
- Fats yield 9 kcal/gram
2) Monosaccharides (Recognize)
- aldohexoses (6): glucose and galactose
i. linear form of glucose anomeric carbon (with carbonyl) can be attacked
by oxygen on carbon 5 and result in two configurations (alpha – down
and beta –up)
ii. in solution, 10% linear, 45% alpha, 45% beta
iii. glucose has OH down on C4, galactose has OH up on C5
- ketohexose (5): fructose
i. C2 (with carbonyl) gets attacked by C5 to make 5 member ring
- Monosaccharides can be linked together via α-1,4 and β-1,4 glycosidic bonds.
i. mammalian enzymes can only digest alpha configuration bond
3) Disaccharides important in nutrition (know compositions and conformation of glycosidic
bonds)
- sucrose – table sugar
i. glucose α-1 to fructose β-2 bond
ii. cannot hydrolyze bond
- maltose - Formed by digestion of starch
i. 2 glucose α-1, 4 bond
- lactose - Milk sugar
i. galactose β-1 to glucose β-4 bond
-Nutitional Terms
- Simple carbohydrates: Monosaccharides and disaccharides
- Complex carbohydrates: Polysaccharides (10+ monosaccharide links) and oligosaccharides (3-
10 units)
