4 



Genetics, Cells, and Chromosomes 



cell wall 



cytoplasm 

 mitochondria 



nuclear membrane 

 chromatin reticulum 



nucleolus 

 vacuole 



cell wall 

 chloroplast 



cytoplasm 

 nucleus 



vacuole 



Fig. 1. Plant cells, (a) An embryonic cell from the root tip of an onion 

 X2800. (6) A parenchyma cell from the mesophyll of a leaf of English 

 ivy. X1400. Camera lucida drawings. 



