8. Eukaryotic Cell Structures & Functions
Mitosis & Meiosis
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in this video we're going to begin our lesson on mitosis and my Asus. And so rather than dividing by binary fission, like what pro carry attic cells do you carry, Attic cells will divide via the process of either mitosis or my yo sis. Now in this video we're going to do a quick overview of mitosis. But later in our course in a different video we'll do a quick overview of mitosis. And so one thing to keep in mind is that for this process of mitosis we have other videos in our biology course that go into a lot more detail. And so if you need those videos from your old biology courses, be sure to go back and check out those videos and our biology course. So that being said mitosis is defined as the a sexual process of dividing the nucleus and the genetic material within the nucleus. And so mitosis can be defined as division of the nucleus and my toes. This will occur in a specific set of cells known as somatic cells, which are really just body cells and pretty much includes all types of cells except for the gannets or the sex cells. Now my toes, this is actually going to start with just one deployed cell or one cell that has two copies of every chromosome. But my toes is ends with two genetically identical cells meaning they have exactly the same DNA. And those cells will be deployed as well, meaning once again that they have two copies of every chromosome. Now, as you can see by this image down below my toast is actually consists of five different phases which are pro fes pro meta phase, meta phase and phase and tell a phase. And so in each of these phases there are characteristic events that occur that once again we cover all of those character characteristic events in our biology videos in our biology course. However, just to do a brief recap of these events and pro phase, what happens is the chromosome 10 is going to coil down and condense into tightly coiled chromosomes that are distinct and visible under a microscope. Then the main topic spindle is also going to begin to form which is made of micro tubules and pro meta phase. The methodic spindle is going to attach to each of the chromosomes at these proteins called kinetic cords, which in this image are these little green circles that you see uh right in the middle here. Then the nuclear envelope is also going to break down in meta phase. All of the chromosomes are going to line up in a single file row, right in the middle of the cell. In anna phase, the sister chroma kids are going to be pulled apart from one another so that each pole gets an identical copy of the D. N. A. And then tell a phase is the last phase, which is pretty much the reverse of pro fes and pro meta phase. And so the nuclear envelope is going to form that my topic spindle breaks down the tightly coiled chromosomes uncoil and unravel back into chroma tin. And following tele phase is the process of psychokinesis, which will actually split the cell cell cytoplasm and split the cell into two. And so this is the overview of mitosis here and in our next lesson video we'll be able to talk about a little memory tool for how you can go about memorizing the order of the phases of mitosis. And then later we'll get to talk more about mitosis. So I'll see you all in our next video.
How to Remember the Order of the Phases of Mitosis
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in this video, we're going to talk about how to remember the order of the phases of my toe, sis. And so this is a strategy that I think about that is really effective for May. And so if it's effective for May, I believe that it can also be effective for you as well. And so when you're thinking about the order of the phases of my toes is personally I think about the M in meta phase, and that's because I think that the M N meta phase is the M in the word metal. And so I know that meta phase is going to be the phase that's right in the middle. And so if I know that there are five phases, total meta phase is going to be the one in the middle. And that means that there are going to be two phases that come before, and there are going to be two phases that come after. And so I start here with Metta phase being the middle phase. And then what you need to know is that the root pro is a route that means before and so pro meta phase and pro fes both have this route. That means before pro meta phase is going to be the phase that comes just before metaphor. So it comes right before meta fades pro meta phase and then pro phase is just going to come before everything else. And so pro fes the root pro again means before, So it just comes before everything. So now you've got these first three in the correct order, Then you think about the A N and a phase. And I think, hey, the A in Anna phases for the a N after. And so Anna phase is going to come just after the middle phase meta phase. And so anna phase comes right here at this position. And then you think about the T in tele phase and you think, Hey, the tea and tele phases for the tea and tail end because tele phase is coming at the tail end of my toe, sis. And so if you're able to remember those details there, then you'll be able to remember the order of the phases of mitosis. No problem every time. And so this year concludes our lesson known how to remember the order of the phases of my toast is, and we'll be able to get some practice applying these concepts as we move forward in our course, I'll see you all in our next video.
The correct sequence for the phases of mitosis is:
a) Prophase - prometaphase - anaphase - metaphase – telophase.
b) Prophase - prometaphase - metaphase - anaphase – telophase.
c) Prometaphase - prophase - metaphase - anaphase – telophase.
d) Metaphase - anaphase - interphase - prophase – telophase
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in this video, we're going to begin our overview of my Asus, which is one of the ways that some specialized eukaryotic cells can divide. Now one thing I want to point out before we continue is that in this video we're only going to be doing an overview of my Asus and in our biology course we have a set of videos that go into a lot more details of both mitosis and my Asus. And so if you need to make sure to go check those out. And so my oasis is actually going to start with a deployed cell just like mitosis starts with a deployed cell. However, in my aosis the deployed cell is a specialized cell called a germ cell and a germ cell is the precursor cell to what are known as gannets or sex cells such as the sperm and males and the eggs and females. And so my Asus is going to start with a deployed germ cell. But mitosis is actually going to end with four genetically diverse cells or four cells that have different or unique D. N. A. And these cells are going to be hap Lloyd gametes meaning that they have only one copy of every chromosome or half the number of chromosomes as a deployed cell. And once again they are gametes which means that they are sex cells such as again uh sperm and male or egg and female. Now the overall process of mitosis is actually broken down into two rounds of cell division that scientists refer to as my Asus one and my Asus two. Now my Asus one is also sometimes referred to as reduction all division because it reduces the ploy the number. Um and deployed is just referring to the number of sets of chromosomes and it does this by separating homologous chromosomes. And so in my Asus one basically what happens is a deployed germ cell and deployed is also represented by the variable to end A deployed germ cell is going to divide into two half Lloyd daughter cells. And so this is just the first round of cell division in my aosis. So this is the halfway point of mitosis. And so in the second round of cell division mitosis in mitosis to which is known as equation all division because it maintains an equal ploy the number after the division, meaning that it maintains the same number of sets of chromosomes. And so it does this by separating what are known as sister chroma ted's rather than separating homologous chromosomes. And so essentially what happens in mitosis to which is a continuation of mitosis. one uh the hap Lloyd cells from my Asus one are going to each divide, producing a total of four. Once again genetically diverse hap Lloyd Grammys as we mentioned up above here. And so if we take a look at this image down below, we can get a better understanding of this overview of mitosis which again is broken up into mitosis one and mitosis too. And so notice over here on the left hand side we're showing you a germ cell which is a deployed cell and that's represented by two n. And so in interphase one which is the phase that occurs before mitosis even begins. The germ cell is going to replicate its DNA. It's going to duplicate its DNA and then it will enter into my Asus one or reduction aled division which is represented here in this phase. And so in this uh my Asus one cell division basically this germ cell is going to divide to produce to hap Lloyd daughter cells and it's gone from being a deployed cell to hap Lloyd cells which means that it is a reduction all division because deploy the numbers decreased and then what we have here is my Asus two follows mitosis one it's really continuation. And so each of these hap Lloyd cells is going to divide to create a total of four cells as you see here and these four cells are going to be hap Lloyd gametes once again meaning that they have half the number of chromosomes and that they would turn into either sperm cell and male or an excel and females. And so really this process of mitosis is used specifically for forming game, it's the formation of sex sells and so this year concludes our brief overview of my Asus and once again if you need more details of my Asus be sure to go check out those videos that we have in our biology course. That being said I'll see you all in our next video
In Meiosis I, cytokinesis usually occurs after telophase I and produces:
a) Four diploid cells.
b) Two haploid cells.
c) Four haploid cells.
d) Two diploid cells.
Four diploid cells.
Two haploid cells.
Four haploid cells.
Two diploid cells.
In Meiosis II, ________ cells are divided into 4 ___________ daughter cells.
a) Diploid; Haploid.
b) Haploid; Diploid.
c) Haploid; Haploid.
d) Diploid; Diploid.