1. Carbohydrates are the Largest Group of Biomolecules
Composing 50% of Earth’s Biomass
Cellulose
Chitin
Cell surface receptor molecules (ABO blood types)
Nucleotides (e.g ATP)
Lactose

2. Carbohydrates Are Polyhydroxy Aldehydes and Ketones
Carbohydrates include monosaccharides, disaccharides, trisaccharides, oligosaccharides and polysaccharides
aldose
(aldehyde)
ketose
(ketone)
glucose
(chain form)
fructose
(chain form)
lactose

3. High Fructose Corn Syrup…
Natural corn syrup contains mainly glucose – enzymatic isomerization produces fructose, which has a sweeter taste. Cheap source of sweetener.
glucose
isomerase
glucose
fructose

4. Carbohydrate Terminology
Monosaccharides: Simplest carbohydrates, 3-7 carbon atoms in chain with C=O at C1 or C2
D-glyceraldehyde
D-erythrose
D-ribose
D-glucose
Triose (3C)
Tetrose (4C)
Pentose (5C)
Hexose (5C)

5. Fischer projection formula of
Drawing Carbohydrate Structures
Carbohydrates contain one or more stereocenters (except dihydroxyacetone) and may be represented by Fischer projection formulas
equal to
Fischer projection formula of
D-glucose
Carbonyl carbons are placed at the top and the carbon skeleton runs along the vertical axis

6. D- and L-glucose are enantiomers
Naturally Occurring Carbohydrates Are of the D-Configuration
D-Sugars have the OH group on the sterogenic center furthest from the carbonyl carbon on the right
L-Sugars have the OH group on the sterogenic center furthest from the carbonyl carbon on the left
D-glucose
L-glucose
D- and L-glucose are enantiomers

7. Physical Properties of Carbohydrates
Sweet tasting
Relative sweetness varies - fructose sweeter than glucose
Polar
Many carbohydrates water soluble
Many insoluble in organic solvents (diethyl ether)
High melting points
Water soluble
Organic soluble

8. Monosaccharide Structures
Monosaccharides can undergo intramolecular cyclization reactions to form hemiacetals
Chair form
(more realistic)
Haworth projection
rotate
cyclize
b-anomer
b-anomer
D-glucose
a-anomer
a-anomer

9. Pyranose and Furanose Structures
Anomeric carbon
Pyranose
Six-membered ring containing O
b-D-glucopyranose
pyran
Anomeric carbon
Furanose
Five-membered ring containing O
b-D-ribofuranose
furan

10. Disaccharides and Polysaccharides
Disaccharides: Two monosaccharides linked via glycosidic bond.
Lactose
Galactose (left) and glucose (right) monomers
Polysaccharides: Polymers of monosaccharides linked via glycosidic bonds. “Complex carbohydrates”

11. Amylose and Amylopectin Are Glucose Polymers Found in Starch-Containing Foods
a-(1-4)-glycosidic bonds
a-(1-4)-glycosidic bonds
and
a-(1-6)-glycosidic bonds
Amylose
Linear polymer
Amylopectin
Branched polymer
Humans digest starch – we have the enzymes to hydrolyze the a-(1-4)-glycosidic bonds

12. b-(1-4)-glycosidic bonds
Cellulose is a Linear Polymer of Glucose Linked viab-(1-4)-Glycosidic Bonds
Cellulose
b-(1-4)-glycosidic bonds
Humans and other non-ruminant animals lack the enzymes to hydrolyze b-(1-4)-glycosidic bonds in cellulose, so it is excreted unchanged (fiber).

13. Glycogen Is a Highly Branched Polymer of Glucose
Glycogen and the enzyme glycogenin –
a glycosyltransferase involved in glycogen synthesis
Extensive branching allows cells to quickly access glucose

14. ABO Blood Types Due to Different Carbohydrates on Red Blood Cell Surface

15. Carbohydrates on RBCs Act as Antigens That May be Attacked by Antibodies

16. Nucleotides Are N-Glycosides
Adenosine
(RNA, ATP)
2-Deoxyadenosine
(DNA)

17. Polynucleotides Are Covalently Linked via 3’,5’-Phosphodiester Bonds
Thymine (T)
Adenine (A)
Phosphodiester linkage
Cytosine (C)
Guanine (G)