1. CARBOHYDRATES
LECTURE-01

2. Carbohydrates – polyhydroxyaldehydes or polyhydroxy-ketones of formula (CH2O)n, or compounds that can be hydrolyzed to them. (aka sugars or saccharides)
Monosaccharides – carbohydrates that cannot be hydrolyzed to simpler carbohydrates; eg. Glucose or fructose.
Disaccharides – carbohydrates that can be hydrolyzed into two monosaccharide units; eg. Sucrose, which is hydrolyzed into glucose and fructose.
Oligosaccharides – carbohydrates that can be hydrolyzed into a few monosaccharide units.
Polysaccharides – carbohydrates that are are polymeric sugars; eg Starch or cellulose.

3. Aldose – polyhydroxyaldehyde, eg glucose
Ketose – polyhydroxyketone, eg fructose
Triose, tetrose, pentose, hexose, etc. – carbohydrates that contain three, four, five, six, etc. carbons per molecule (usually five or six); eg. Aldohexose, ketopentose, etc.

4. Reducing sugar – a carbohydrate that is oxidized by Tollen’s, Fehling’s or Benedict’s solution.
Tollen’s: Ag+  Ag (silver mirror)
Fehling’s or Benedict’s: Cu3+ (blue)  Cu2+ (red ppt)
These are reactions of aldehydes and alpha-hydroxyketones.
All monosaccharides (both aldoses and ketoses) and most* disaccharides are reducing sugars.
*Sucrose (table sugar), a disaccharide, is not a reducing sugar.

5. Glucose (a monosaccharide)
Plants:
photosynthesis
chlorophyll
6 CO H2O C6H12O O2
sunlight (+)-glucose
(+)-glucose starch or cellulose
respiration
C6H12O O CO H2O energy

6. Animals
plant starch (+)-glucose
(+)-glucose glycogen
glycogen (+)-glucose
(+)-glucose fats or aminoacids
respiration
(+)-glucose O2 6 CO H2O energy

9. (+)-glucose? An aldohexose
Emil Fischer (1902)
Four chiral centers, 24 = 16 stereoisomers

11. Ruff degradation – a series of reactions that removes the reducing carbon ( C=O ) from a sugar and decreases the number of chiral centers by one; used to relate configuration.

12. Kiliani-Fischer synthesis
Kiliani-Fischer synthesis. A series of reactions that extends the carbon chain in a carbohydrate by one carbon and one chiral center.

13. Epimers – stereoisomers that differ only in configuration about one chiral center.

14. Exists only in solution. There are two solids:
α-glucose m 146o [α] =
β-glucose m 150o [α] = +17.5
In water each mutarotates to an equilibrium with [α] = +52.7
(63.6% β / 36.4% α)

15. LECTURE NO. 2

16. CYCLIC STRUCTURE OF CARBOHYDRATES

17. Addition of alcohols to aldehydes/ketones:

24. Disaccharides:
(+)-maltose “malt sugar”
two glucose units (alpha)
(+)-cellobiose
two glucose units (beta)
(+)-lactose “milk sugar”
galactose & glucose
(+)-sucrose “table sugar”
glucose & fructose

27. Polysaccharides
starch
cellulose
Starch 20% amylose (water soluble)
80% amylopectin (water insoluble)
amylose H2O  (+)-maltose
(+)-maltose H2O  (+)-glucose
starch is a poly glucose (alpha-glucoside to C-4)

28. Amylopectin + H2O  (+)-maltose
(+)-maltose H2O  (+)-glucose
Also a polyglucose, but branched every units:

29. Cellulose is a polyglucose with a beta-linkage: