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Cell Biology

Learn the toughest concepts covered in Cell Biology with step-by-step video tutorials and practice problems by world-class tutors

16. Cell Division



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Hi in this video, we're gonna be talking about psychokinesis. So psychokinesis is kind of the last step. Or maybe right after in phase where it actually will cleave the cytoplasm that was supposed to be highlighted. Clean the cytoplasm into two separate cells. So there's a few things that we need to know about this. So the first thing is that the methodic spindle is disassembling. So it doesn't really play that big of a role. But before it starts disassembling, what it does is it actually positions this complex called the cleavage furrow. So the cleavage furrows position in the cell, which is where the cell is gonna divide depends on positioning by the main topic spindle. So the cleavage furrow, it's kind of just this puckering of the plasma membrane where it's going to split into. So if I were to draw it real fast, the cleavage furrow is here where the sales have puckered in. And that positioning where that is divided depends on my topic spindle. Now, that's super important, right? Because we don't want it puckering here and here because you may be like missing some organelles or something or you may be missing some some chromosomes. So the way you want it dividing where it's supposed to exactly where it's supposed to. So each daughter cell gets half of everything. Right? So this positioning is super important. Um So most of the time this is going to be symmetrical division to ensure that both daughter cells get exactly half of everything that's been replicated, they get half of the replicated chromosomes, half of the replicated organelles. But sometimes this actually can be a symmetrical especially when the cell needs to develop into a different type of cell type. Maybe the cell type needs so many more mitochondria than the other. And so most of the time it'll be symmetrical cleavage bureaus but sometimes it won't. But either way the positioning is super important. So another factor of psychokinesis is the contract. I'll ring. This begins forming during an A. Phase. It's made of acting and medicine. And it works to put this force on the plasma membrane assisting in the actual like cutting of this. So eventually that pressure has to actually separate the two cells. So the contract I'll ring contracts it and actually provides that pressure so that the cells will split into two. So there's an important protein here called Ro A. It's a G. T. P. S. Remember it's gonna hydraulics. GTP. And it's super important in triggering the contract all ring formation. So this is great. Um All super important in dividing cells. But when we talk about plant cells which we haven't really mentioned a lot. Um So we're just gonna mention briefly but plant cells have an extra step because they need to create a new cell wall after division. So how they do that is there's this structure called the fragment plast. And it is formed by micro tubules as well. So micro tubules. Super important cell division. And it helps assemble the new cell wall. So what it does is it forms a structure called the cell plate and this is a cell wall precursor. This will eventually become the cell wall. But it's just so simple and it's a precursor so hasn't formed yet and it forms it inside the cell and eventually it as the cell matures and completely divides, it will form a real cell wall. So here we get two cells are about to divide. But what you get here is this contract, I'll ring made up of acting a medicine that comes in contracts. This area here provides that pressure and we'll split the cell into two and notice here that this is actually symmetrical, division everything. And this cell is present also in this one. So Super important. So with that let's not move on.

Which of the following structures is responsible for cleaving the cell into two cells?


Which of the following structures is a precursor to a cell plate in plant cells?