TEAS 7 Science: Mitosis and Meiosis(The TEAS 7 will have 9 scored questions on life and biological sciences)

TEAS 7 Science: Mitosis and Meiosis(The TEAS 7 will have 9 scored questions on life and biological sciences)Mitosis Division of the a cell's nucleus for growth and repair of the cell. Outcome of Mitosis Two genetically identical daughter cells Steps of Mitosis 1. Interphase 2. Prophase 3. Metaphase 4. Anaphase 5. Telophase Cytokinesis The division of the cytoplasm to form two separate daughter cells. Occurs at end of telophase. Interphase Cell grows, performs its normal functions, and prepares for division. Consists of G1, S, and G2 phases during which DNA replicates. Prophase Longest phase of mitosis, during which the chromosomes condense and become visible. Centrioles separate and move to opposite sides of the nucleus. Nuclear membrane disappears Metaphase Chromosomes line up in the middle of the cell Metaphase = middle Anaphase Chomosomes move apart, from the center to the poles Anaphase = apart Telophase Chromosomes move to opposite ends of the cell and two nuclei are formed. Nuclear membrane reappears. The new daughter cells separate via cytokinesis Meiosis Cell division that produces 4 gamete cells in sexually reproducing organisms, each with half the genetic information of the originating cell Germ cell Reproductive cell that produces ova (eggs) or sperm Gamete Sex cell that contains half the genetic information Sperm or ovum (egg) Steps of Meiosis I Prophase I, Metaphase I, Anaphase I, Telophase I Steps of Meiosis II Prophase II, Metaphase II, Anaphase II, Telophase II What happens at the end Interphase? DNA replicates Does Interphase happen before both mitosis and meiosis? Yes. Homologous chromosomes Chromosomes that have the same sequence of genes, that have the same structure, and that pair during meiosis. Crossing Over Process in which homologous chromosomes exchange portions of their chromatids during meiosis. Chromatid One half of a duplicated chromosome Prophase I Homologous chromosomes pair up and form tetrads. Crossing over occurs Metaphase I Paired homologous chromosomes line up in the center of the cell Anaphase I Homologous chromosomes separate toward opposite poles Telophase I Nuclear membrane forms and cytoplasm divides 2 daughter cells are formed What is the end product of Meiosis I? 2 haploid cells Sister chromatids have not separated (haploid set) Prophase II The first phase of meiosis II. Prophase II is identical to mitotic prophase, except that the number of chromosomes was reduced by half during meiosis I. Metaphase II Sister chromatids line up in the middle Anaphase II Sister chromatids separate to opposite poles Telophase II Nuclear membrane reforms and cytoplasm divides. 4 haploid daughter cells formed Sister Chromatids Joined copies of the original chromosome Haploid Cell having only one complete set of chromosomes. Sperm and ova are haploid cells. Diploid Cells with two complete sets of chromosomes, one from each parent. How many chromosomes do human cells have? 46 (23 pairs) How many chromosomes does a human ovum have? 23 Would a human skin cell undergo meiosis? No, meiosis only occurs in reproductive cells. How many cells are at the end of mitosis? 2 identical diploid cells How many cells are at the end of meiosis? 4 different haploid cells How many cells are at the end of meiosis I? 2 haploid daughter cells, each with 2 sister chromatids Daughter cell Cells produced as a result of cell division Recombination One chromosome breaks off and attaches to another chromosome during reproductive cell division Nuclear membrane Lipid bilayer that surrounds nucleus. Also called nuclear envelope.