![]() ![]() And I'm gonna do it twice, because I'm now dealing with two different cells. So our centrosomes have migrated to the poles. And actually all of meiosis II is very similar to what ![]() And you can just imagine, it's very similar to what Let me draw an arrow here so you can see that we are entering into another phase. So once again, very strong analogy, especially to frankly, So the centrosomes have replicated and they will start to migrate to opposite ends of the cell. Shorter orange chromosome just like that, so they have condensed, and you've actually, each of these cells now will have duplicate centrosomes. You have this chromosome, right over here, and it had a little orange section from the chromosomalĬrossover just like this, and then you have the ![]() Little bit of the magenta that was from the chromosomal crossover back in prophase I, and then you have thisĬharacter right over here that is shorter. Into their denser form, so it's gonna look like this, this, and this. So your nuclear envelope dissolves again, and your chromosomes once again condensing (mumbles) I guess you could say Your nuclear envelope dissolves again, so let me show a dissolving In prophase II, just like in prophase I, and just like in prophase in mitosis, and let me write the phases here, this is prophase II we're talking about, prophase II. So this is one of the cells right over here, and then this is the other cell right over here. To draw it properly, so let me draw it, so let me draw this one first. And in prophase II, now I'm dealing with two cells here, so in prophase II, and I'm gonna do it for both of the cells that I have after I finished meiosis I, so in prophase II, so let me. So you can imagine meiosis II starts with prophase II. But then we get into meiosis II, which will allow us toĬomplete all of meiosis. interphase II, which you could kind of view as a rest period. There can be a rest period where you have an interphase II, and that will depend on the type of cell and the species and all of that, but it is possible, so I'll actually put that over here. Went back into our interphase, "is there kind of a rest period "between our two phases of meiosis?" And the answer is, sometimes. And you might be wondering, "Well, hey, after mitosis, we ![]() This shuffling of genetic material between the maternal and paternal chromosomes during meiosis leads to greater genetic diversity.We had completed meiosis I, and now we're ready to go into meiosis II. During the process, chromosomes can exchange pieces of DNA. During this round, the chromosomes are divided into 23 rods in each of the 4 cells. The two resulting cells contain 23 chromosomes. Once they have found their partner, they line up at the centre of the cell for the first round of division. We have 23 pairs of rods, for a total of 46 chromosomes. Both copies of the same rod are bound together at the middle to form an X. During meiosis, the mother cell copies its DNA molecules and condenses them into rods (chromosomes). Meiosis is similar to mitosis, but it has an extra round of cellular division. Meiosis produces four genetically different cells containing half of the genetic material. DNA in sex cells must undergo another round of division: with 23 chromosomes on one side and 23 chromosomes on the other. But a sex cell can only hold half of the genetic material, since it must unite with the other sex cell to produce a new individual. Regular cells have 23 pairs of chromosomes (for a total of 46 chromosomes), and each pair contains one chromosome from our father and another chromosome from our mother. When sex cells, the sperm and the egg, are involved, cell division is taken to a whole other level! The process is called meiosis. The chromosome pairs then split and move apart toward opposite poles of the cell before it divides into two genetically identical daughter cells. Once the nuclear membrane breaks down, the chromosomes line up in a neat row at the centre of the cell. Both copies of the chromosomes stick together in the middle, which is why they look like an X under the microscope. DNA is then condensed into rod-like structures known as chromosomes. To achieve this, the cell must first make a second copy of all the DNA in its nucleus. The process by which a cell splits into two genetically identical copies is called mitosis. For example, cells are constantly duplicating so that our nails and hair keep growing. (mitosis and meiosis) Our cells reproduce so that we may grow and regenerate. ![]()
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