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Cell Cycle & Meiosis
Cell Cycle, Mitosis and Meiosis
Question | Answer |
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Mitosis | The first stage of cell division in which the nucleus divides. Mitosis results in the formation of two daughter cells with exactly the same genetic information as the parent cell. Mitosis results in the production of two identical diploid cells. |
Meiosis | The process of cell division in which the chromosome number per cell is cut in half to form sex cells. This results in two haploid cells. |
Homologous chromosomes | A pair of chromosomes, one from the male parent and ithe corresponding chromosome from the female parent. |
Diploid | A cell that contains a set of homologous chromosomes--one from each parent. Somatic (body) cells are diploid. |
Haploid | A cell that contains only one set of chromosomes--one from one parent but not both. Haploid cells are sex cells such as egg and sperm cells |
Tetrad | Prior to meiosis, each chromosome is duplicated, therefore, when it pairs up with its homologous chromosome |
Crossing Over | As homologous chromosomes pair up and form tetrads in meiosis I, they exchange portions of their chromatid. This results in the exchange of alleles between homologous chromosomes and produces new combinations of alleles. |
Cell Division | The larger a cell becomes, the more demands it places on its DNA and the more trouble it has moving nutrients and waste across the cell membrane. Before a cell becomes too large, it divides, forming two daughter cells. |
Cytokinesis | The second stage of cell division in which the cytoplasm divides and two daughter cells are formed. |
Chromosomes | The genetic information that is passed on from one generation of cells to the next. Chromosomes are made up of DNA coiled around proteins. |
Chromatids | Before cell division, each chromosome is replicated (copied). Each of the pair of sister chromosomes is called a chromatid. |
Centromere | The attachment site for the two sister chromatids. |
Cell Cycle | The series of events that cells go through as they grow and divide. |
Steps of the Cell Cycle | Interphase, Mitosis, Cytokinesis |
Interphase | That portion of the cell cycle between cell divisions in which the cell grows, performs its required functions and duplicates DNA and important organelles in preparation for cell division |
G1 Phase of Interphase | First phase of interphase in which the cell is growing |
S Phase of Interphase | Second phase of interphase in which DNA is replicated |
G2 Phase of Interphase | Last phase of interphase in which cell organelles are duplicated in preparation for cell division |
Four Phases of Mitosis | Prophase, Metaphase, Anaphase, Telophase |
Centrioles | Cell organelles that help organize spindle fibers for the separation of chromosomes during mitosis. |
Cancer | Cancer results from the inability to control cell growth and division. |
Prophase | The first division of Mitosis in which the chromosomes become visible. The nuclear membrane begins to dissolve. |
Metaphase | The second stage of mitosis in which the chromosomes line up along the middle of the cell. |
Anaphase | The third stage of mitosis in which the sister chromatids are separated and one of each is pulled to each end of the cell |
Telophase | The final stage of mitosis in whcih the chromosomes begin to disperse, the nuclear envelope re-forms around each cluster of chromosomes and the cell is ready for cytokinesis. |