3/28/11 Discussion on Meiosis

Today in class, Mr. Finley told us we were going to get our most previous test back as soon as the last person took their test. Talking about tests, we will have one, a week from tesday. Hopefully, before the end of the marking period(April 20) we will get back our lab reports.

Then, we continued off with our human example/simulation of meiosis which we left off on thursday(check thursday's blog if you are confused). We continued with prophaseII, in which the nucleur membrane disappears, chromosomes condense, and the two centrioles move to the opposite ends of the cell. After that, we decided to only focas on one cell because there were too many people. Then in metaphaseII the humans lined up on either side of the plate and the spindle fibers were attached to them. During anaphaseII, the people in the middle of the room (chromosomes) seperate (besty stage). Lastly, during telophaseII, the nucleur membranes reapear, forming four cells. We did not go over cytokinesesII because it was not neccasry, since everyone understood that the nucleaur membranes split...etc.

The more important discussion was when we started to take notes on reproduction! YAY! At first we talked about a single celled organism such as a peremecium cell and how it goes through mitosis to reproduce. We compared single cell reproduction to mutlicell reporduction, such as us humans. We said that the process of reproduction/meiosis starts off when two haploid cells( containing 50% DNA) such as an egg and a sperm cell, meet up in the same place at the same time. When the two cells join together, they form a zygote. After that, the zygote goes through mitosis to create more cells and to get bigger. The zygote starts to become into an infant. To add on, the infant goes through even more mitosis to become an adolescent. Especially during this time of a males life, around 12-17 years old, meiosis starts occuring in his testes. Keep in mind that mitosis is still hapening everywhere else in the body to repair and create more cells. Some key terms that you should know are that there are three different gametes(sex cells); eggs, sperm, and pollin. Continuing with the process of meiosis, when a adolecsent grows and becomes a man, he marries a woman and happily engages sexual intercourse. The purpose is to basically get the two halpoid cells in the same place at the same time. Once they meet and join they create a process called fertilization. Then the whole process of meiosis repeats. However, the main difference between a female going through meiosis than a male, is that she does it when she is in her stage of a zygote and an infant. Therefore, by now she would already be done with it.

I hope I have made you more clear on this topic that we learned today. If you have any questions, leave a comment and I will try my best to reply.

SK

#4 blog