| Flap 1 | Flap 2 |
| gene | segment of dna that transmits information from parent to offspring |
| chromosome | a rod shaped structure that forms a single dna molecule |
| chromatids | the two copies of each chromosome |
| centromere | a protein disk that attaches two chromatids together |
| homologous chromosomes | the two copies of each chromosome |
| diploid | when a cel contains two homolougues of each chromosome |
| gametes | egg and sperm cells |
| haploid | when a cell contains only one homologue of each chromosome |
| zygote | a fertilized egg cell and the first cell of a new individual |
| trisomy | when a diploid cell has an extra chromosome |
| karyotype | the collection of chromosomes found in an individual's cell |
| Down syndrome | The traits produced by having an extra copy of chromosome 21 |
| disjunction | when a cell divides normally each chromosome and it's homologue seperate |
| nondisjunction | when one or more chromosomes fail to seperate properly |
| amniocentesis | when a physician uses a needle and a syringe to remove a small amount of fluid from the amnion |
| amnion | the sac that surrounds the fetus |
| chorionic villi sampling | when a physician analyzes a karyotype |
| mutations | changes in an organisms genetic material |
| deletion | when a fragment of a chromosome breaks off, it can be lost when the cell divides causing a mutation |
| duplication | when a chromosome fragment attaches to it's homologous chromosome which will then carry two copies of a certain set of genes |
| inversion | when the fragment reattaches to it's original chromosome in the reverse orientation |
| translocation | when a fragment joins a nonhomologous chromosome |
| autosomes | of 23 pairs of chromosomes in human somatic cells, 22 pairs are the same in males and females |
| sex chromosomes | the chromosomes that differ between males and females |
| binnary fission | form of asexual reproduction that produces identical offspring |
| cell cycle | life of a eukaryotic cell |
| G1 | growth fase of the cell |
| s phase | when dna is copied |
| G2 phase | preperation for nuclear division is made |
| m phase | the phase where mitosis occurs |
| mitosis | when the nucleaus of a cell divides in 2 nuclei |
| c phase | when the cytoplasm divides |
| cytokinesis | the process in which the cytoplasm divides |
| interphase | the g1, g2, ands phases |
| spindle fiber | the cables in the spindle |
| kinetochore | a disk protein |
