232 Plant Biology 



formaldehyde are intermediate products and, even though they may be 

 poisonous, it is theorized that they are joined to some other group so 

 quickly that they do not have time to produce toxic effects on the living 

 protoplasm. The successive steps might be stated as follows: 



(1) CO2 ^ H2O _^ H2CO3 



(Carbon dioxide) (Water) (Carbonic acid) 



(2) H2CO3 + H2O ^ CH.O; + H2O2* 



(Formic acid) (Hydrogen peroxide) 



(3) CH2O2 + H2O -^ CH2O + H2O2* 



(Formaldehyde) 



(4) By adding successive CH2O -> C6H12O6 



(Sugar) 



Another theory suggests that the intermediate product of photosynthe- 

 sis may be a complex chlorophyll compound. It is known that chloro- 

 phyll absorbs certain photons of light (radiant energy), thus becoming 

 chemically active. When in this state the chlorophyll probably unites 

 with carbon dioxide and water to form an unstable, intermediate product. 

 An enzyme converts the chlorophyll compound to sugar. The successive 

 steps might be stated as follows: 



(1) CO2 + H2O + Chlorophyllf + Light energy -^ Chlorophyll 

 (Carbon (Water) carbonate 

 dioxide) 



(2) Chlorophyll carbonate + Enzymef + H2O -^ Sugar + O2 



Recent experiments on photosynthesis by Graffon, Brown, and Fager 

 utilizing radioactive tracer technics, seem to reveal that there is a pri- 

 mary, intermediate product of carbon dioxide and water formed which is 

 known as "Factor B." The latter is chemically unidentified at present 

 but behaves like an acid and is rapidly used by the plant in its metabolic 

 processes. Proper identification of this factor and future work with 

 radioactive chemicals which can be traced may assist in the explanation 

 of the process. 



Biochemical Aspects of Photosynthesis. — Plants do not derive their 

 foods, as usually stated, from the soil. Plants cannot live alone on the 

 inorganic salts and water absorbed by the root hairs from the soil but 

 must have proteins, carbohydrates, and fats just as animals must. Both 

 plants and animals require much of the same type of food, but the green 



*Split by cmzymes into water and oxygen. 



fin the process the chlorophyll and enzyme are converted to their original state. 



