| A | B |
|---|
| Anaphase | a phase of mitosis and meiosis in which the chromosomes separate |
| asexual reproduction | the production of offspring that does not involve the union of gametes (156) |
| autosome | a chromosome that is not a sex chromosome (146) |
| binary fission | an asexual cell division of prokaryotes that produces identical offspring (148) |
| cell cycle | the events of cell division; includes interphase, mitosis, and cytokinesis (149) |
| cell plate | a membrane that divides newly forming plant cells following mitosis (151) |
| centriole | a structure that appears during mitosis in animal cells (150) |
| centromere | a region of the chromosome where the two sister chromatids areheld together and which is the site of attachment of the chromosome to the spindle fibers during mitosis (146) |
| centrosome | a dark body containing a centriole in animal cells but not in plant cells; spindle fibers radiate from the centrosome in preparation for mitosis (150) |
| chromatid | one of two identical parts of a chromosome (146) |
| cleavage furrow | the area of the cell membrane that pinches in and eventually separates the dividing cell (151) |
| crossing-over | the exchange of genes by reciprocal segments of homologous chromosomes during meiosis (153) |
| cytokinesis | the division of the cytoplasm of one cell into two new cells (149) |
| diploid | a cell that contains both chromosomes of a homologous pair (147) |
| gamete | a reproductive cell (153) |
| genetic recombination | the new mixture of genetic material after crossing-over has taken place (154) |
| G 0 phase | a phase of the cell cycle in which the cell is not dividing and its DNA is not replicating (149) |
| G 1 phase | the first period of interphase, in which the cell doubles in size (149) |
| G 2 phase | the final period of interphase in which the cell undergoes rapid growth and prepares for mitosis (149) |
| haploid | having only one chromosome of each homologous pair (147) |
| histone | a protein molecule that DNA wraps around during chromosomeformation (145) |
| homologous chromosome | one of a pair of morphologically similar chromosomes (146) |
| independent assortment | during meiosis, the random distribution of genes from different chromosomes to the gametes (154) |
| interphase | a period of cell growth and development that precedes eukaryotic cell nuclear division (149) |
| Karyotype | a picture of an individual's chromosomes (147) |
| Kinetochore | a disk-shaped protein found in the centromere region of a chromosome that attaches the chromosomes to the mitotic spindle (150) |
| kinetochore fiber | a spindle fiber that extends from the centrosome at one pole of the cell to a chromatid during mitosis (150) |
| meiosis | the process of nuclear division that reduces the number of chromosomes in a cell by half (148) |
| metaphase | the second phase of mitosis during which all the chromosomes move to the cell’s equator (150) |
| mitosis | eukaryotic nuclear division (148) |
| mitotic spindle | the array of spindle fibers that serve to divide the chromatids during nuclear division (150) |
| M phase | mitosis; the phase of cell division in which the nucleus divides (148) |
| Oogenesis | the production of mature egg cells (155) |
| polar body | one of two small cells produced and discarded during each of the two meiotic divisions that yield the haploid egg (156) |
| polar fiber | fibers that extend across a dividing cell from centrosome to centrosome (150) |
| prophase | the first stage of mitosis and meiosis characterized by condensation of chromosomes (150) |
| sex chromosome | a chromosome that determines sex (146) |
| sexual reproduction | the production of offspring from the combination of genetic material from two parent organisms (156) |
| spermatid | in meiosis a haploid cell that develops into a mature sperm cell (156) |
| spermatogenesis | the production of sperm cells (155) |
| S phase | the second period of interphase during which replication of DNA occurs (149) |
| spindle fiber | one of the microtubules that extend across a dividing eukaryotic cell; assists in the movement of chromosomes (150) |
| synapsis | the pairing of homologous chromosomes during meiosis (153) |
| telophase | the final stage of mitosis during which a nuclear membrane forms around each set of new chromosomes (151) |
| tetrad | a group of two homologous chromosomes during meiosis (153) |
