Chemical Composition of Wood Flashcards
As an organic material, wood’s principal element is ______.
Carbon
The major organic chemical constituents that make up the cell walls of wood are ______, ______, and ________.
cellulose, hemicellulose and lignin
Taken together, cellulose and hemicellulose are referred to as __________.
HOLOCELLULOSE
Holocellulose the polysaccharide fraction of the woody element comprising about ________
60-70%
Cellulose ______ long chain of glucose units that polymerize into microfibrils.
40 -50%
Man can digest starch (a polysaccharide) but not _____ which animals can digest because of cellulose enzymes present in their guts or stomach.
cellulose
Hemicellulose ______ matrix substance of the cell wall composed of two types of sugar molecules: xylans and glucomannans.
(20-35%)
Lignin _______ made of intractable material which acts as the cementing substance of wood
(15-35%)
Secondary Components of Wood:
*Tannins
*Volatile oils
*Resins
*Gums, latex, dyes, andother organic substance
*Ash –approximately0.5 to 1% of the
wood substance (inorganic
extraneous materials)
Classes of Carbohydrates
- Monosaccharides
- Oligosaccharides
- Polysaccharides
These are also called simple sugar.
Monosaccharides
Monosaccharides they can _______ be broken down to smaller sugar.
no longer
Monosaccharides are small compounds with _____ carbon atoms.
3 to 9
Consist of up to 9 monosaccharide units.
Oligosaccharides
Oligosaccharides are further classified according to the number of monosaccharide units that they contain. Among them are:
a)Disaccharides
b)Trisaccharides
c)Tetrasaccharides, and other sugars
They consist of two monosaccharides linked by a single glycosidic bond;
Example is cellobiose
Disaccharides
They consist of three monosaccharides linked by two glycosidic bonds.
Trisaccharides
__________, _________ and other sugars that contain less than 10 sugar units.
Tetrasaccharides; pentasaccharides
These are complex polymers composed of a large number of monosaccharide units joined together by several glycosidic linkages.
Polysaccharides
Polysaccharides It can be further classified into:
*Homopolysaccharides
*Heteropolysaccharides
- Only one kind of monosaccharide makes up the polymer.
Homopolysaccharides
- At least two different kinds of monosaccharide make up the polymer.
Heteropolysaccharides
