72 Introductory Biology 



4. Why is it so essential that the individual chromosomes divide lengthwise dur- 

 ing the metaphase stage? 



5. When each chromosome divides lengthwise, what causes each resulting half 

 to migrate toward opposite ends of the cell? 



6. What are the controlling forces which start and stop the process of mitosis? 



7. When injured tissues repair themselves by mitosis, what starts and stops the 

 process? What is happening when injuries fail to repair? 



8. What is the probable relationship between mitosis and cancer? Suggest a 

 method of preventing this disease. 



9. Why do we study young tissues in mitosis? What, in general, is the rate of 

 mitosis in older tissues? 



10. What is the relationship between mitosis and heredity? 



11. List the chief differences between the process of mitosis in animals and plants. 



SELECTED REFERENCES i 



Schrader: Mitosis: The Movements of Chromosomes in Cell Division, Columbia 



University Press. 

 White: The Chromosomes, Chemical Publishing Co., Inc. 



