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Meiosis
Study Guide Questions
Term | Definition |
---|---|
Asexual Reproduction | No union or combination of gametes----Offspring comes from one parent: are identical to parent----Mitosis occurs to make new offspring or replace cells----No meiosis occurs. |
Sexual Reproduction | The union of gametes (egg and sperm)----Genetic information IS exchanged during meiosis----Two parents are involved. |
Diploid Cell | Contains both pairs of Homologous Chromosomes----Humans: each cell has 46 chromosomes (23 pairs)----Body/somatic cells/occurs during meiosis. |
Meiosis and Sex Cells | Takes place only in gametes or sex cells (egg or sperm)----Creates sex cells that are used in fertilization----Egg and sperm join to form a zygote which develops into an embryo and then into a fetus. |
Sex Cells | Males and females have the same number of chromosomes in their cells BUT: Male cells have an XY chromosome while females have an XX chromosome. |
Meiosis Overview | Involves 2 cell divisions |
Meiosis Division 1 | After 1st division, the number of chromosomes divided in 1/2 in each cell because homolougous pairs pull apart. Each chromosome still has double the DNA----Homologous chromosomes exchange genes; new cells are different from parent cells: there are 2 cells |
Meiosis Division 2 | The sister chromatids separate----Cells split into 4 cells----Each cell has 23 chromosomes (1 chromatid from each homologous pair) and now the correct amount of DNA. |
Egg and Sperm | Sperm: 4 produced with each cell division Egg: 1 egg called an Ootid gets all the cytoplasm----3 polar bodies have chromosomes but no cytoplasm and are NOT released. |