■ The chromosomes are seen 

 as a tangle of fine threads 





2 



The chromosomes are 

 separating from each other 

 and are thickening 



• 





3 



Each chromosome has 

 split into two distinct 

 threads 







4 



'^ Ac ^ 



S 





\ 



The newly divided chromosomes are moving away from each other 



L 



^ Pk 



S'^^'X 



•^^^TP»# 





H 



9 



Both sets of chromosomes collect together at opposite sides of the cell and cell division takes 

 place. At the end of the process there are two distinct cells. The cell walls are not visible 



3 Chromosomes in the nucleus of cells from the growing tip of 

 onion root in different stages of cell division. (Photographs of fixed 

 and stained preparations reproduced by courtesy of Dr S. H. Revell, 

 Chester Beatty Research Institute) 



