40 



PLANT PHYSIOLOGY 



in water solutions, by means of the polarimeter, which measures 

 the angle through which the plane of polarization is rotated. 

 This is widely applied in analyses in factories engaged in sugar 

 production and other similar industries. 



HCOH OHCH 



HCOH 



HCH 



HCOH 



HC— CHoOH 



HO— C— H 



HO— C— H 



HOCH 



Z-Arabinose 



HCOH 



d-Glucose 



OHCH 



HCOH OH— C— CHoOH 



HO— C— H 



H2C 



d-Fructose 



Glucose and fructose are very widespread in plants; there is 

 not a single plant cell that does not contain some amount at 

 least of one of these hexoses. As will be seen later, they represent 

 the basic substance consumed by protoplasm in the process of 

 respiration and participate in many other important biochemical 

 processes. 



Disaccharides are combinations of 2 molecules of monosac- 

 charides joined through oxygen. Their formation is accom- 

 panied by the removal of 1 molecule of water, as illustrated by 

 the following reaction: 



2C6H12O6 '^ C12H22O11 + H2O. 



