1. CARBOHYDRATES
(CH2O)n
© 2016 Paul Billiet ODWS

2. Organization Monosaccharides, Disaccharides, Polysaccharides
5C pentoses (eg ribose, deoxyribose)
6C hexoses (eg glucose, fructose, galactose)
GLUCOSE
CH2OH C H OH O
RIBOSE OH H
CH2OH C O
© 2016 Paul Billiet ODWS

3. Glycoside linkage to form disaccharides
The two sugars are joined by condensation and may be broken by hydrolysis
CH2OH C H OH O
© 2016 Paul Billiet ODWS

4. CH2OH C H OH O
+ H2O
© 2016 Paul Billiet ODWS

5. Different monosaccharides can be used
sucrose = glucose-fructose
lactose = glucose-galactose
maltose = glucose-glucose
© 2016 Paul Billiet ODWS

6. Polysaccharides Macromolecules Common ones based upon glucose
Branched polysaccharides
Amylose & amylopectin (starches) are synthesised in plants.
Glycogen is synthesised in animals, more highly branched than starches = more compact
Unbranched polysaccharides
Cellulose in plant cell walls
© 2016 Paul Billiet ODWS

7. CARBOHYDRATE FUNCTIONS
Sugars (mono and disaccharides) small molecules soluble in water:
Maintenance of osmotic balance (e.g. plant cell turgidity);
transport of energy reserves (e.g. glucose in blood or sucrose in sap);
energy substrate (respiration and photosynthesis);
energy store (sugar cane);
flavouring (fruits); reward (nectar);
precursors (building blocks) of polysaccharides, nucleotides and amino acids
© 2016 Paul Billiet ODWS

8. CARBOHYDRATE FUNCTIONS
Polysaccharides Large molecules insoluble in water:
Osmotically inactive carbohydrate storage, (seeds, roots, chloroplasts)
Structural (cellulose in plants).
© 2016 Paul Billiet ODWS