Prometaphase

by Jason Amores Sumpter
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so after pro phase, the second phase of mitosis is pro meta phase. Now it's important to note that in some of your textbooks pro meta phases also sometimes referred to as late pro Fes and so in some of your textbooks, they won't even mention pro meta phase as a phase. Instead, they'll just batch all of the events of pro meta phase into pro fes, because again, sometimes pro meta phase is referred to as late pro phase. So that's important to keep in mind. If your textbook does not have a pro meta phase phase in it, then that means that your textbook is just batch ing the events of pro meta phase with pro phase the phase that comes right before. Now there are really two specific events that they're going to take place during pro meta phase. That's important for you all to know. The first is that the nuclear envelope or the nucleus itself is going to degrade or, in other words, break down. And so when the nuclear envelope degrades or breaks down, it's actually going to expose the chromosomes to the cytoplasm. And that means that the might, ah, tick spindle that has been forming is capable of linking to the chromosomes by attaching to specific proteins called kinetic core proteins that air found within the Centrum ear of the chromosomes. Recall the Centrum ear, which is not to be confused with the, uh, central zone. The central here is the waste position of the chromosomes where the two sister chromatic IDs are going to meet, and so notice down below again, in our image, we're showing you the full all of the stages of mitosis. But we're not focusing on these over here were specifically focusing on the second phase of my toes is pro meta phase. And so notice on the left we're showing you the first phase pro phase and the image that we talked about in our last lesson video. And in this video, we're talking about pro meta phase, which is this image right here. And the events that are taking place are right here in the middle. And so the first thing that's going to happen is the nuclear envelope is going to degrade or break down. In other words, and so you can see over here in pro fes, the nucleus is intact. But over here in pro meta phase notice that the nuclear envelope has been broken down. It's degrading, which is why we're showing it in these small pieces. And so that is going to expose the chromosomes to the cytoplasm of the cell and that allows the might Arctic spindle to attach to these kinetic or proteins that air found, uh, in the Centrum ears of the chromosome. And so again, the Centrum ear is going to be the waste position. So right here in these positions of the chromosomes, you'll find these little green proteins that are the kinetic core proteins. And this is where the micro tubules of the my Tadic spindle can attach. And when these micro tubules attached to the kinetic core is, they can move the chromosomes around. And that's what we're going to see is going to happen in the next phase. And so this here concludes pro meta phase, and in our next phase of my toast is we're gonna talk about meta phase itself, so I'll see you all in that video