dine nucleotides. The stroma is composed of unpigmented lipoproteins 

 which are probably the location of enzymes involved in secondary 

 reactions of photosynthesis (e.g., carbon dioxide fixation and phosphate 

 transfer). 



Figure 3-16. (a) Schematic Diagram of the Submicroscopic Structure 

 of the Plant Chloroplast as Seen in Cross-section, (b) Schematic Diagram 

 of the Three-dimensional Structure of the Chloroplast in the Higher Plant. 

 (Fig. (a) from von Wettstein. D.. 1959. '"Developmental Changes in Chloro- 

 plasts and their Genetic Control." in '"Developmental Cytology," D. Rudnick 

 (Ed.), Ronald Press, New York, N. Y., Fig. 23, p. 129. Courtesy of Dr. D. 

 von Wettstein, Forest Research Institute, Stockholm, Sweden. Fig. (b), 

 courtesy of Dr. D. von Wettstein.) 



Photosynthesis, or the light-activated synthesis of carbohydrate from 

 carbon dioxide and water by green plants, is absolutely essential for 

 maintenance of cells, particularly animal cells, which are dependent on 

 the oxidation of exogenous carbohydrate as a means of carrying out 



42 / CHAPTER 3 



