Cell Division in Relation to Reproduction - 63 



16. Distinguish between isogamy and heterog- 

 amy; cite two examples in each case. 



17. Divide the following cells into two lists ac- 

 cording to whether they are haploid or dip- 

 loid: (a) fertilized eggs; (b) the tissue cells 

 of man's body; (c) sperm cells; (d) unfer- 

 tilized eggs; (e) the zygospore of Spirogyra; 

 (f) the zygospore of Ulothrix; (g) the macro- 

 gamete of Pandorina; (h) a spore mother 

 cell; (i) the spore of a higher plant. 



18. In the life cycle of each of the following or- 



ganisms, specify where fertilization and meio- 

 sis take place: (a) man; (b) Spirogyra; (c) any 

 high plant; (d) Amoeba. 

 19. Carefully explain each of the following state- 

 ments: (a) certain features of mitosis very 

 plainly indicate that among the various struc- 

 tures of a cell the chromosomes are of para- 

 mount importance; (b) jointly, meiosis and 

 fertilization provide a basis for biparentat 

 inheritance. 



FURTHER READINGS 



"How Cells Divide," by D. Mazia, in "The 

 Living Cell," special issue of Scientific Amer- 

 ican, September 1961. 

 The Cell, vol. 3, Mitosis and Meiosis, ed. by 



J. Brachet and A. E. Mirsky; New York, 1961. 

 General Cytology, 3d ed., by E. D. P. DeRob- 

 ertis, W. W. Nowinski and F. A. Saetz; Phila- 

 delphia, 1960. 



