| A | B | 
| chromosome | tightly coiled lengths of DNA wrapped around protein cores | 
| karyotype | a set of chromosomes in which the homologous pairs are matched and arranged by size | 
| diploid | a cell that contains 2 sets of chromosomes | 
| haploid | a cell which contains a single set of chromosomes | 
| sex chromosomes | chromosomes that determine the sex of an organism, in humans the 23d pair | 
| human female | XX | 
| human male | XY | 
| mitosis | eukaryotic cell division of the nuclei | 
| cytokinesis | cellular division at the end of mitosis | 
| cell cycle | life span of a cell including growth and division | 
| tumor | clump of cells caused by cancer | 
| cancer | uncontrolled cell division and growth | 
| mutation | change in the genetic code | 
| gamete | egg or sperm, a haploid reproductive cell | 
| meiosis | cellular division that produces gametes | 
| crossing over | the exchange of genetic information between homologous chromosomes |