| A | B |
|---|
| asexual reproduction | process in which a single cell or set of cells produces offspring that inherit all their genetic material from one parent |
| sexual reproduction | process in which genetic material from two parents combines and produces offspring that differ genetically from either paren |
| chromatin | combination of DNA and protein molecules, in the form of long, thin fibers, making up the genetic material in the nucleus of a eukaryotic cell |
| chromosome | condensed threads of genetic material formed from chromatin as a cell prepares to divide |
| sister chromatid | one of a pair of identical chromosomes created before a cell divides |
| centromere | region where two sister chromatids are joined tightly together |
| cell cycle | sequence of events from the production of a eukaryotic cell to the time the cell itself reproduces |
| interphase | stage of the cell cycle during which a cell carries out its metabolic processes and performs its functions in the body |
| mitotic phase | stage of the cell cycle when a cell is actively dividing |
| mitosis | process by which the nucleus and duplicated chromosomes of a cell divide and are evenly distributed, forming two daughter nuclei |
| cytokinesis | process by which the cytoplasm of a cell is divided in two; usually follows mitosis and meiosis |
| spindle | framework of microtubules that guide the movement of chromosomes during mitosis and meiosis |
| centrosome | region of cytoplasmic material that in animal cells contains structures called centrioles |
| prophase | first stage of mitosis and of meiosis I and II, when the already replicated chromosomes condense |
| metaphase | second stage of mitosis and of meiosis I and II when the spindle is fully formed and all of the chromosomes are held in place |
| anaphase | third phase of mitosis and of meiosis I and II, in which the sister chromatids separate and move toward the poles of the spindle |
| telophase | final stage of mitosis and of meiosis I and II, in which the chromosomes reach the spindle poles, nuclear envelopes form around each set of daughter chromosomes, and the nucleoli reappear |
| cell plate | disk containing cell wall material that develops in plant cells during cytokinesis, eventually dividing the cell into two daughter cells |
| cancer | disease caused by severe disruption of the mechanisms that normally control the cell cycle |
| benign tumor | mass of cells that remain at their original site |
| malignant tumor | mass of abnormal cells resulting from uncontrolled cancer cell division |
| metastasis | spread of cancer cells beyond their original site in the body |
| tetrad | group of four chromatids formed during prophase I of meiosis by the two sister chromatids in each of the two homologous chromosomes |
| karyotype | display of a person's 46 chromosomes |
| homologous chromosome | one of a matching pair of chromosomes, one inherited from each parent |
| sex chromosome | one of two chromosomes of the 23rd pair of human chromosomes, which determine an individual's gender |
| diploid | having two homologous sets of chromosomes |
| gamete | egg or sperm sex cell that contains a single set of chromosomes, one from each homologous pair |
| haploid | having a single set of chromosomes |
| fertilization | the fusion of the nucleus of a haploid sperm cell and the nucleus of a haploid egg cell, forming a diploid zygote |
| zygote | diploid cell formed when the nucleus of a haploid sperm cell fuses with the nucleus of a haploid egg cell |
| meiosis | type of cell division that produces four cells, each with half as many chromosomes as the parent cell |
| crossing over | xchange of genetic material between homologous chromosomes during prophase I of meiosis |
| genetic recombination | new combination of genetic information in a gamete as a result of crossing over during prophase I of meiosis |
