Introduction to Cell Division

by Jason Amores Sumpter
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in this video, we're going to begin our introduction to cell division. Now. Cell division could be defined as the process of a single parent cell dividing or splitting into greater than or equal to two or mawr daughter cells. And so this term daughter cells, you'll hear your professor use it occasionally from time to time and you'll see it throughout your textbooks as well. And so this term daughter cells is really just referring to the cells that result from cell division or cell splitting now moving forward. In our course, we're going to talk about three main types of cell division, and we have these three main types number 12 and three down below. And, of course, the numbers in our text correspond with numbers that you see down below throughout our image. And so the first main type of cell division that we're going to introduce is called binary vision. And really, the most important thing that you should know about binary vision is that this is a type of pro carry ah tick cell division, and so on. Lee pro carry attic cells like bacteria or archaea are going to divide by binary vision but eukaryotic cells that do have a nucleus they do not divide by binary fission. And so let's take a look at our image down below, over here on the left hand side to clear some of this up and so notice that we're showing you an image of binary vision. And once again, binary fission is a type of cell division that Onley occurs in pro carry, ah, tick cells like bacteria or archaea that do not have a nucleus. And so notice here we're showing you a single parent, pro carry attic cell that does not have a nucleus and notice that it's DNA is just floating on the inside of the cell in the cytoplasm in a region called the nuclear oId, which that is review from our older lesson videos. But the big point here of binary vision is that it starts with a pro carry attic cell and noticed that by the end of the process there are two cells to pro carry attic cells, and so these two cells are turned the daughter cells, since thes air, the cells that result from the cell division and notice that each daughter cell down below has a copy of the DNA, which is in green, And that means that this original copy of the DNA is going to have to get replicated or duplicated at some point in this process. But we'll talk more about DNA replication later in our course and again, the biggest take away for binary fission is that this is how pro carry attic cells divide. Now, the other two types of cell division that we're going to introduce, uh, two and three are types of Eukaryotic cell division. And so we're gonna look at them specifically as they apply to the human life cycle. And so the second type of cell division that we're going to talk about is my toe sis. Whereas the third type of cell division that we're going to talk about is my yo sis. Now I'll admit at first glance, my toe sis and my oh sis, they sound really, really similar. And in fact, it turns out not only do they sound similar, but they also have a lot of similarities. But my toasts and my oh sis are different processes and so moving forward in our course, it's going to be very important for you guys to be able to distinguish between my toe Sis and my oh sis, now moving forward in our course were mainly going to try to break down mitosis first. But then, after we're done breaking down my toe, sis, then we'll switch over to discuss my Oh, sis. Now, just to give you a little bit of background information about my toasts and my oh, sis, my toast again is a eukaryotic cell division that is going to produce what are known as somatic cells. And somatic cells are really just body cells that do not get passed down to the next generation. And so somatic cells or body cells would include cells like our heart cells are liver cells and our skin cells. Now, human somatic cells are what are known as deployed cells, and we'll talk more about deployed later in our course. But really, what deployed means is that there are going to be two copies of every chromosome inside these cells, and so deployed is going to be symbolized using a symbol called to end. And so any time you see to end, you know that it represents a deployed cell, okay, and again you can think the end here represents the number of copies of chromosomes, and, of course, deployed cells have two copies of every chromosome. Now, my oh sis. On the other hand, the third type of cell division is also a eukaryotic cell division. But instead of producing somatic cells like might, assist does my oh Sis produces what are known as GAM, it's and game. It's are really just the fancy scientific name for sex cells such as the sperm and male and the eggs and females. Now human GAM. It's on the other hand, Unlike human somatic cells, they're not deployed, and so they don't have two copies of every chromosome. Instead, human gametes are what are known as hap Lloyd cells, and Hap Lloyd kind of sounds like half, so they have half the number of chromosomes. So instead of having two copies of every chromosome, they're only going to have one copy of every chromosome. And again, if this, uh, deployed and Hap Lloyd concept was a little bit difficult for you to understand, we're going to talk more about it later in our course. So this is more so of foreshadowing for you guys to get toe, understand these terms a little bit early. And so let's take a look at our image down below, over here on the right hand side to better distinguish my toe sis and my oh sis. And so what's important to note again is that this images showing the human life cycle so which you'll notice here at the top are two adults. Notice that there is a male and there is a female. And the males produce what our produce gametes Ah, that air called sperm cells. And so this process is going to be my Asus. My oh sis is the process that is going to produce the sex sells the gaming such as the sperm and the egg on the egg. Over here is the sex cell or the gaming of the female. Now notice that these gametes here are Hap Lloyd. They have the end symbol here, which represents half Lloyd, so that means that they have half the number of chromosomes. They only have one copy of every chromosome. And that's because during sexual reproduction, the sperm and the egg gametes are going to merge together in a process that's called fertilization. So you can see the sperm here merging with the egg, and they each have half the number of chromosomes. They each have one copy of every chromosome. So when they merge together, the resulting cell, which is called a zygote, ends up having two copies of every chromosome, so it becomes a deployed cell. And so the zygote here is a deployed cell, the very first sell off a human. And so this Zygo ends up growing and growing and growing into many trillions and trillions of cells through the process called mitosis and my toast. This is what takes a deployed cell and creates mawr deployed cells on. It allows the single cells I go to grow into a baby, and it also my toast. This will also allow the baby to grow up into a toddler and to grow up into a kid into a teenager and eventually grow up into a full adult either the male or the female, and notice that humans adults are all deployed so you can see the zygote is deployed. The baby has deployed cells, and the adults also have deployed cells which are to end and the only ones that air hap Lloyd are going to be the game. It's the sex cells, which are on Lee. Uh, well, I only have one copy of every chromosome. Now again, this here is just the introduction to Might Asus, which basically represents this entire green region here. And then my Oh sis, which represents the small section here of the life cycle and again moving forward in our course were mainly going Thio, introduce my toast this first. And then later in our course, we'll talk more about my Oh, sis. So this year concludes our introduction to cell division And again as we move forward in our course, we're going to get to learn a lot more about each of these cell division, so I'll see you all in our next video.