Allele		The process of producing many identical copies of a gene; also the production of many genetically identical copies of an organism.
Diploid		Mitosis followed by cytokinesis.
Metaphase		The process whereby relatively unspecialized cells, especially of embryos, become specialized into particular tissue types.
Telomere		Meiosis followed by cytokinesis.
Recombination		The division of the cytoplasm and organelles into two daughter cells during cell division; normally occurs during telophase of mitosis.
Locus		The nucleotides at the end of a chromosome that protect the chromosome from damage during condensation, and prevent the end of one chromosome from attaching to the end of another chromosome.
Gamete		A single DNA double helix together with proteins that help to organize the DNA.
Haploid		The region of a replicated chromosome at which the sister chromatids are held together until they separate during cell division.
Telophase		The formation of new combinations of the different alleles of each gene on a chromosome; the result of crossing over.
Sexual Reproduction		Referring to a cell with pairs of homologous chromosomes.
Cell Cycle		Microtubules organized in a spindle shape that separate chromosomes during mitosis or meiosis.
Cell Division		Pain
Cell Plate		The exchange of corresponding segments of the chromatids of two homologous chromosomes during meiosis.
Karyotype		The stage of mitosis in which the chromosomes, attached to spindle fibers at kinetochores, are lined up along the equator of the cell.
Duplicated Chromosome		Offspring that are produced by mitosis and are therefore genetically identical to each other.
Meiotic cell division		Referring to a cell that has only one member of each pair of homologous chromosomes.
Autosome		The pair of chromosomes that usually determines the sex of an organism; for example, the X and Y chromosomes in mammals.
Biology		A eukaryotic chromosome following DNA replication; consists of two sister chromatids joined at the centromeres.
Mitotic cell division		The physical location of a gene on a chromosome.
Kinetochore		A type of nuclear division, used by eukaryotic cells, in which one copy of each chromosome (already duplicated during interphase before mitosis) moves into each of two daughter nuclei; the daughter nuclei are therefore genetically identical to each other.
Chromatid		A chromosome that occurs in homologous pairs in both males and females and that does not bear the genes determining sex.
Meiosis		In eukaryotic organisms, a type of nuclear division in which a diploid nucleus divides twice to form four haploid nuclei.
Mitosis		In mitosis, the stage in which the sister chromatids of each chromosome separate from one another and are moved to opposite poles of the cell; in meiosis I, the stage in which homologous chromosomes, consisting of two sister chromatids, are separated; in meiosis II, the stage in which the sister chromatids of each chromosome separate from one another and are moved to opposite poles of the cell.
Anaphase		In plant cell division, a series of vesicles that fuse to form the new plasma membranes and cell wall separating the daughter cells.
Cloning		Splitting of one cell into two; the process of cellular reproduction.
Prophase		A chromosome that is similar in appearance and genetic information to another chromosome with which it pairs during meiosis; also called homologous chromosome .
Checkpoint		A preparation showing the number, sizes, and shapes of all chromosomes within a cell and, therefore, within the individual or species from which the cell was obtained.
Chromosome		Reproduction that does not involve the fusion of haploid sex cells. The parent body may divide and new parts regenerate, or a new, smaller individual may form as an attachment to the parent, to drop off when complete.
Interphase		In animal cells, a short, barrel-shaped ring consisting of nine microtubule triplets; a microtubule-containing structure at the base of each cilium and flagellum; gives rise to the microtubules of cilia and flagella and is involved in spindle formation during cell division.
Binary fission		The stage of the cell cycle between cell divisions; the stage in which chromosomes are replicated and other cell functions occur, such as growth, movement, and acquisition of nutrients.
Centromere		One of several alternative forms of a particular gene.
Chiasma(chiasmata)		A haploid sex cell formed in sexually reproducing organisms.
Asexual reproduction		The first stage of mitosis, in which the chromosomes condense, the spindle forms, the nuclear envelope breaks apart, and the spindle fibers attach to the kinetochore of each sister chromatid. Also, the first stage of meiosis: In meiosis I, the homologous chromosomes pair up and exchange parts at chiasmata; spindle fibers attach to homologous chromosomes. In meiosis II, the spindle re-forms and attaches to the kinetochores of each sister chromatid.
Spindle Microtubule		In the eukaryotic cell cycle, one of several stages at which various proteins regulate the ability of the cell to proceed through the cycle.
Crossing over		A form of reproduction in which genetic material from two parent organisms is combined in the offspring; normally, two haploid gametes fuse to form a diploid zygote.
Centriole		The sequence of events in the life of a cell, from one division to the next.
Cytokinesis		The process by which a single bacterium divides in half, producing two identical offspring.
Sex Chromosome		A protein structure that forms at the centromere regions of chromosomes; attaches the chromosomes to the spindle.
Differentiation		A point at which a chromatid of one chromosome crosses with a chromatid of the homologous chromosome during prophase I of meiosis; the site of exchange of chromosomal material between chromosomes.
Clone		In mitosis and both divisions of meiosis, the final stage, in which the spindle fibers usually disappear, nuclear envelopes re-form, and cytokinesis generally occurs. In mitosis and meiosis II, the chromosomes also relax from their condensed form.
Homologue		One of the two identical strands of DNA and protein that forms a replicated chromosome. The two sister chromatids are joined at the centromere.