Part 1 of Meiosis

I am going to talk about some key parts of meiosis that everyone should know or hopefully will get a better understanding of after this discussion. Meiosis, a type of cell division, produces an egg and a sperm cell. Meiosis has two types of nuclear division. I will begin with interphase 1, though this starts before meiosis begins, the genetic material is duplicated/replicated. When the first division of meiosis begins, Prophase 1 will begin and this is where the chromatin condenses. Now, the most important part of Prophase 1 should start. The term is called CROSSING OVER. The meaning is as simple as the actual word. A exchange occurs between the two sister chromatids and the chromatids actually physically break off and then it is attached to a different homologous (same) chromosome. Everyone should know this term because most likely it will be on the test (probably short answer portion). Metaphase 1 now starts and this is when the homologous chromosomes line up in the equator (around the middle). Then the homologous pairs seperate but the sister chromatids stay together and this is called Anaphase 1. Last but not least, Telophase 1 begins and two daugther cells form. They have only one chromosome from the other homologous pair. I am not sure if this video will work on your computers but go ahead and try it but i would suggest watching it after i post part II of my discussion on meiosis. There are two websites, but i only will tell you one because the second one is right below it, hill.com/sites/0072437316/student_view0/chapter12/animations.html. Paste this into google and there will be search results, click the one that says Biology 201(about the fourth or fifth result). Once the page loads, scroll down and you should see in bright red letters Too See an animation on meiosis go to: The third and fourth URL, are the two vids i wanted to show you. The third has audio and once you click it (pick the one that says, stages of meiosis) and the fourth does't have audio but both are great videos. Also be aware, if you are watching these videos in the school library that Ms. Johnson will probably activate VISION CONTROL , and when you try to explain that it is for school, it is already too late.