Next up we're going to do an overview on cell division. So we're going to be talking about the cell cycle specifically focusing on mitosis and understanding the implications or importance of cell division. So again solid division is the process of creating new cells and this is going to be very important for various things like our growth tissue repair as well as reproduction when we're talking about meiosis the cell division is just a small part of the cell cycle or the whole life cycle of a particular cell. The components of the cell cycle involve various things. So one we have interphase, which is going to be where the cell spends about 90 percent of its lifetime this is just the phase where the cell is carrying out regular functions. And this is also the part where they prepare to divide. And within interface there's going to be various phases or sub-phases within it. So it has G1, has S, and G2. And to just kind of simplify what these mean the G phases, G1 and G2, this is where the cell just grows hence the word G or the letter G in it. While within this S phase right over here S stands for DNA synthesis. So here in the S phase this is where that DNA replication happens and again that DNA replication is important to ensure that the copy cells that result from the cell division all have the same amount of DNA and can function regularly. So again cells can't just divide without replicating DNA it does need to happen first so all of this needs to happen before cell division can actually occur and cell division is going to be either mitosis or meiosis. We're going to focus primarily on the somatic cell division or the phases of mitosis so again this occurs after interphase or after the preparation phase. And these are the sequence of events or phases that occur within mitosis itself the first part is going to be prophase and it's going to be followed by metaphase, anaphase, telophase, and eventually cytokinesis. Let's go ahead and first talk about prophase. Prophase is the first part of mitosis where one the DNA condenses into these structures called chromosomes. So typically DNA is this loose stringy substance within our cells. This loose stringy configuration is really hard to work with if we need to separate it so in order for cells to efficiently divide out DNA they need to be condensed into chromosomes so that they're easier to work with. So that's why chromosomes form within prophase. Aside from that within prophase the nuclear envelope breaks down again remember that DNA is located within the nucleus the nuclear membrane needs to break down a bit so that we can actually reach the DNA inside the nucleus so the nuclear membrane breaks down. Aside from that the last major thing that occurs within prophase is that this protein structure called the mitotic spindle forms and this mitotic spindle is what's going to be responsible for separating chromosomes. And next up we have metaphase metaphase is where these chromosomes line up in the middle. And at this point if you're seeing these little lines that's an indication that this is the base where the mitotic spindle attaches to the chromosomes. And this is in preparation before we split them apart the specific phase where they're split apart is going to be anaphase so we can write that chromosomes are pulled apart. And this is again done via the mitotic spindle. And next up we have telophase and cytokinesis which we'll just kind of group as a it together because they do happen pretty much at the same time. So telophase and cytokinesis happens after we separate DNA so at this point that cell is now able to split into two or is ready to split into two. So what happens within this is that the chromosomes uncoil we don't need them tightly packed anymore they can go back to their regular orientation so they can uncoil aside from that we need to protect that DNA so that the nuclear envelope again reforms around that DNA and lastly the cell splits into two and again the cells that result have the same amount of DNA as the original. And again that is due to DNA replication doing what it does. So let's end this video with this practice question. In which part of mitosis do chromosome structures form? Go ahead and pause the video and answer this question on your own. And if you selected prophase that would be the correct answer this is the phase where DNA condenses into these tightly packed structures called chromosomes so that DNA is easier to break apart.