Transcript Polysaccharides

• Polymers made of 100’s of monosaccharide
units (MUs)
• A condensation reaction occurs between
each MU and are held together with
glycosidic bonds
• Molecules can be branched or unbranched
• Are insoluble and not sweet to taste
• Storage polysacs are folded to give
compact molecules
• Structural polysacs are coiled or straight
chained
Polysaccharides
•Starch:
•Glycogen:
•Cellulose:
plant storage
animal storage
structural support
• Main carbohydrate food reserve in
plants
• A polymer made up of many a glucose
molecules held together by
GLYCOSIDIC BOND
• Made of two compounds – amylose and
amylopectin
• Long chains of a glucose molecules
linked by 1,4 glycosidic bonds
• Chains are coiled to form a spiral held
in place by hydrogen bonds
• Long chains of a glucose molecules
linked by 1,4 glycosidic bonds
• Has some 1,6 glycosidic linkages giving
it a branched structure
What makes starch a
good food store?
• Compact
– for storage
• Insoluble
- no affect on osmotic
balance of cell
• Readily converted into
sugar
– many side branches
• similar to
amylopectin, made up
of chains of a
glucose
• But has many more
1,6 glycosidic side
branches
Function
• Very compact storage molecule found
in mammalian liver (and muscles)
• Increased branching allows for quick
hydrolysis to release glucose
• Means very quick energy release
• Made up of long, unbranched chains
of b glucose
• Individual chains are linked to each
other by hydrogen bonds
• Overall structure is of long, strong
microfibrils
• These form layers at different angles
to each other, giving strength
CELLULOSE
H
O
b glucose
HO
H
H
H
HO
HO
O OO
OH
H
H
HO
b glucose
O
b glucose
OH
H
O
H
O
H
OH OH
H H
OH
H
OH
b glucose
O OOH
H HO
H H HO
H
O
H
OH
Function
• Structural polysaccharide in plants
• Cellulose cell walls provide strength
to plant cells
• H-bonds prevent water entering the
molecule
• Makes it resistant to hydrolysis from
enzymes