CARBOHYDRATES 21 



5. Hexuronic acids, CoHioO? : u-glucuronic acid, D-mannurordc acid, D-galac- 

 turonic acid 

 E. Heptoses 



1. Ketoheptoses, CtH^Ot : u-mannoheptulose, sedoheplulose 

 II. Disaccharides, dsH^iiOn 



A. Anhydrides ^ of glucose and galactose : lactose, melibiose 



B. Anhydride of jrlucose and fructose: sucrose 



C. Aniiydrides of glucose and glucose: maltose, iso-77ialtose, cellobiose, gen- 

 tiobiose, trehalose 



D. Anhydrides of a hexose and a hexuronic acid (aldobiuronic acids) : cello- 

 biuronic acid, geutiubiuronic acid 



III. Ti-isaccharides, CisHaaOio 



A. Anhydride of galactose, glucose, and fructose: raffinose 



B. Anhydride of glucose, fructose, and glucose : melizitose 



IV. Polysaccharides 



A. Homopolysaccharides (anhydrides of single monosaccharides) 



1. Pentosans, (C5H804)j: xylan, araban 



2. Hexosans 



a. Glucosans, (CcHioOs)^ : cellulose, starch, dextrin, glycogen, bacterial 



dex trait. 

 h. Fructosans, (CeHioOs)^: inulin, bacterial levari 



c. Galactosans, (CuHioOs)*: snail galactogen 



d. Mannosans, (CeHioOs)^: vegetable nut manjian, salep mavnan 



e. Polyglucosamine : ^ chilin 



f. Polyuronides,' (C«H808)x 



(1) Polygalacturonic acid: pectic acid 



(2) Polymannuronic acid : alginic acid 



B. Heteropolysaccharides (anhydrides of several monosaccharides) 



1. Hemicelluloses: alkali-soluble polysaccharides associated with cellulose in 

 wood, straw, cornstalks, and other fibrous plant tissues. On hj'drolysis, 

 form mainly D-xylose, together with L-arabinose, D-glucose, uronic acids, 

 and other sugars. 



2. Plant gums: gums from injured trees or bushes, mostly water-soluble, and 

 forming D-glucuronic acid and other sugars on hydrolysis. Examples: 

 gum arable, viesquitc gum, cherry gum. 



3. Plant mucilages: polysaccharides extractable from the seeds, roots, leaves, 

 and bark of various plants, forming colloidal solutions. Examples: gum 

 gatto, linseed mucilage, agar-agar. 



4. Mucopolysaccharides: water-soluble polysaccharides found in animals and 

 often associated with protein. Usually form aminohexoses and (or) hexu- 

 ronic acids, as well as other sugars when hydrolyzed. Examples: hya- 

 luronic acid, heparin, choiidroitin sulfate, pneumococcus polysaccharides, 

 blood-group polysaccharides. 



V. Substances Related to Carbohydrates 

 A. Sugar alcohols, open chain 



1. Four carbon type, C4Hio04: erythntol 



2. Five carbon type, Cr-Hi-Oi: xylitul, arabitol, nbilul 



3. Six carbon type, (hexitols), CoHiiOe: mannitol, sorbitol, dulcitol 



An anhj-dride is a product formed by removing the elements of water from another 

 substance or substances. Frecjuently an H atom is split out of one moleculi' and an 

 (JH fjroup from another, and tlie residues unite to form the anliydrido. 



-polysaccharide giving glucosamine and acetic acid on hydrolysi.s. 



^ Polysaccharide giving a uronic a«'id on hydrolysis. 



