172 - The Cell 



How do the algae differ from most higher 

 plants: (a) as to habitat; and (b) as to gen- 

 eral structure? 

 To what extent does absorption in Clos- 

 terium and other algae depend upon diffu- 

 sion and osmosis? Explain. 

 Define the term "photosynthesis," specifying 

 precisely the kinds of matter and energy that 

 are involved. 



One plant is exposed to green light, and an- 

 other to red light. Predict the relative rates 

 of photosynthesis in the two plants. Explain. 

 In photosynthesis light energy is utilized, not 

 to reduce (X)., but to liberate oxygen from 

 H..O. Explain the experiments that substan- 

 tiate this conclusion. 



Can animals and plants utilize CO., in the 

 formation of organic compounds? To what 

 extent, il any. is light energy involved in 

 such processes? 



Is chlorophyll the only pigment capable of 

 participating in photosynthesis? Explain. 

 What is a granum? Why is the fine structure 

 of the granum important in relation to 

 photosynthesis? 



Explain the importance of heavy oxvgen 

 (0 ,s ), radiocarbon (C 14 ), and paper chro- 

 matography, in relation to modern research 

 on photosynthesis. 



To what extent can isolated chloroplasts 

 carry on photosynthesis? Explain. 

 Explain the importance of ATP and TPNH., 

 in relation to photosynthesis. 

 Differentiate between "light reactions" and 

 "dark reactions" in the metabolism of green 

 plant cells. 



What is a photon? How is the energy con- 

 tent of a photon related to the wavelength 

 ot light? 



16. 

 17. 



19. 



20. 



23. 



24. 



What are fluorescence and phosphorescence? 

 Explain. 



Differentiate between cyclic and noncyclic 

 pholophosphorylation. Explain the impor- 

 tance of these processes. 



Briefly summarize the contributions of: (a) 

 Ruben: (b) Arnon; (c) Priestley: and (d) Cal- 

 vin to our understanding of photosynthesis. 

 Explain the importance of phosphoglvceric 

 acid (PGA) in relation to CO., assimilation. 

 Explain the importance of ribulose diphos- 

 phate in relation to the fixation of CO,,. 

 Explain the general importance of photosyn- 

 thesis: 



a. from the "viewpoint" of plants 

 I), from the "viewpoint" of animals 

 State five ways in which glucose may be used 

 in the cells of a typical plant, in each case 

 specifying such chemical reactions as may be 

 involved. 

 Compare animal and plant cells, as regards: 



a. the origin of amino acids utilized in 

 metabolism 



b. ways in which amino acids are utilized 

 in metabolism 



Carefully explain why nitrate (—NO,,) salts 

 are plant foods of great importance. Why are 

 sulfates and phosphates likewise needed by 

 green plants? 



Account for the fact that considerable quan- 

 tities of nitrogenous wastes are formed in the 

 metabolism of animals, but not in the me- 

 tabolism ot plants. 



Construct a table showing the main points of 

 contrast between the holophytic and holo- 

 zoic types of nutrition. 



Point out five essential similarities between 

 the holozoic and holophytic types of nutri- 

 tion. 



FURTHER READINGS 



"The Role of Light in Photosynthesis." by 

 D. I. Arnon, in Scientific American , Novem- 

 ber 1960. 



"The Path of Carbon in Photosynthesis." by 

 M. Calvin, in Science, vol. 135, March 16, 

 1962. 



3. Great Experiments in Biology, ed. by M. 

 Gabriel and S. Fogel: see sections on photo- 

 synthesis by Priestley. Ingenhousz. Ruben, and 

 others; Englewood Cliffs, N. J., 1955. 



4. The Plant World, 4th ed.. by H. J. Fuller and 

 Z. B. Carothers; New York, 1963. 



