| A | B |
|---|
| gametes | sex cells produced by complex organisms |
| fertilization | fusion of the nuclei of the male and female gametes |
| zygote | the single cell formed from fertilization |
| meiosis | cell division that results in gametes with half the number of chromosomes as the parent cell |
| somatic cells | body cells; cells that are not gametes |
| homologous chromosomes | pairs of chromosomes similar in size, shape, and content |
| diploid | 2n; cells that have all homologous chromosomes (somatic cells) |
| haploid | n; half the diploid number of chromosomes; (gametes) |
| tetrad | the group of four chromatids that combine during synapsis |
| crossing-over | process by which tetrads exchange parts of their segments |
| gonads | specialized organs where gametes develop |
| ovaries | female gonads |
| ova | eggs; female gametes |
| testes | male gonads |
| sperm cells | male gametes |
| hermaphrodites | commonly slow moving organisms that have both ovaries and testes |
| gametogenesis | process by which gametes develop in the gonads |
| oogenesis | formation of eggs in the ovaries |
| spermatogenesis | formation of sperm in the testes |
| oogonium | immature egg cells that form in the follicle |
| follicles | spherical sac where mature egg develops |
| primary oocyte | develop from oogonia and stop at prophase until sexual maturity |
| secondary oocyte | oocyte that has undergone meiosis |
| polar body | resulting cell that develops from unequal division of an oocyte; will die off |
| ootid | will result in a mature egg |
| spermatogonia | immature sperm cell that develops in the testes |
| primary spermatocyte | spermatogonium that has increased in size |
| seconday spermatocyte | sperm cell that has undergone meiosis |
| spermatid | will develop into a mature sperm cell |
| acrosome | found in the head of a sperm cell that contains enzymes to penetrate the egg |
| external fertilization | gametes fuse outside of the body of the female |
| internal fertilization | gametes fuse inside the body of the female |
