Carbohydrates
Wang Xuan
Carbohydrates
• elements: C H O
• general formula: Cx(H2O)y
• 3 groups: monosaccharide,
disaccharide,
polysaccharide
Monosaccharides
•
•
•
•
(CH2O)n
triose (3C) : glyceraldehyde
pentose (5C) : ribose deoxyribose
hexose (6C) : glucose fructose galactose
Structures
pentoses：
glucose
hydroxyl group (-OH)
α-glucose & β-glucose
isomers
Functions
1. commonly used as a source of energy in
respiration, glucose
2. building blocks for larger molecules,
glucose/ribose/deoxyribose
Carbohydrates
Wang Xuan
Disaccharides
Structures
• glycosidic bond
• condesation
• hydrolysis
Polysacchrides
• plants: starch cellulose
• animals: glycogen
starch
glycogen
cellulose
starch
• starch: α-glucose condesations
1. Consists of amylopectin and amylose
2. Amylose forms a stiff helical structure via 1,4-glycosidic
bonds
3. Amylopectin is branched via 1,6-glycosidic bonds
4. Both are compact molecules → starch can be stored in
small space
glycogen
1. Branched, storage,
polymer of α-glucose linked
via glycosidic bonds
2. Found in skeletal muscle
and liver
3. Chains are linked by
alpha-1,4-linkage,
branches are linked by
alpha-1,6-linkages
cellulose
1. Polysaccharide
consisting of long β-glucose
chains
2. Linked together by
hydrogen bonds to form
microfibrils
3. Structural function is a
important component of
plant cell walls
Homework
Draw a mindmap
about
carbohydrates