420 CHAPTER 45 



QUESTIONS FOR DISCUSSION 



45.1. What is revealed regarding nucleocytoplasmic interrelationships from the study of F? 

 Of temperate phages? 



45.2. What evidence can you present that COo-sensitivity is due to a virus rather than a 

 normal chromosomal gene? 



45.3. In proving the existence of extranuclear genes which operations (recombinational, 

 mutational, functional, chemical) were we utilizing? Did we include their capacity 

 for self-replication? Why? 



45.4. Discuss the genetic control of chlorophyll production in corn. 



45.5. Do you think the study of nucleocytoplasmic interrelations in Paramecium has any 

 bearing upon differentiation processes in multicellular organisms? 



45.6. What unique advantages does Paramecium have as an experimental organism for 

 genetic investigations? 



45.7. Certain paramecia are thin, due to a completely recessive nuclear gene, //;. What is 

 the phenotypic expectation for the clones derived from exconjugants of a single 

 mating of + + X + tIP. 



Is your expectation affected by the occurrence of cytoplasmic mixing? Why? 



45.8. According to the definition of a chromosome given on page 19, would you consider 

 kappa to be, or contain, a chromosome? Explain. 



45.9. Keeping in mind the difficulties of proving the existence of extranuclear genes, which 

 do you think represents the primary genetic material in cellular organisms, nuclear 

 or extranuclear genetic material? Explain your decision. 



45.10. Does adaptive enzyme formation provide an example of a feed-back system? Ex- 

 plain. 



