General Biology

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12. Meiosis

Introduction to Meiosis

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Introduction to Meiosis

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in this video, we're going to begin our introduction to my oh, sis. And so it's important to note that even before my ASUs takes place, a deployed cell must first replicate its DNA and make proteins for cell division in a process that we know as interphase. And so really, what we're saying here is that even before my oh, sis takes place, interface still needs to take place. And so if we take a look at our image down below notice that this orange region that you see over here is representing interphase as we discussed it in our previous lesson videos when we were talking about the cell cycle. And so even before my oh sis takes place, interphase first needs to take place, and interphase is still going to have a G one phase and s phase and a G two phase. And, of course, the S phase is where the DNA is going to get replicated. And so, even before my oh sis can take place, interface takes place and DNA replication is going to occur. And so notice that my oh sis here is indicated by this region of our image. And really, when we look at the process of my oasis. It's actually broken down into two parts. My ASUs one followed by psychokinesis and my ASUs two, followed by psychokinesis. And so ultimately, as we move forward in our course, we'll talk Mawr and Maura about this process of my oh, sis, and break it down much further. But really, what you can see here is that my oh, sis eyes not going to be a cyclic process that regenerates the same types of cells like what might assist does. And so notice that instead of forming a full circle that starts and ends at the same place, you can see that with this process of my oh sis, it really creates a linear type fashion here that is not going to be cyclic and regenerate the same types of cells on again as we move forward. In our course, we're going to talk Mawr and mawr about my oh, sis. But really the biggest take away that you can get about this process of my oh sis, is that it's going to start with a deployed germ cell, and it's going to end with four genetically diverse Hap Lloyd cells or more specifically, Hap Lloyd gam eats and recall gametes are just the sex cells either sperm or eggs. And so what is this germ cell here, This deployed germ cell. Well, the germ cell is again a deployed cell. So it's going to have two copies of every chromosome. And it's the deploy. Sell the access, The precursor for making game. It's and so the germ cell eyes going to ultimately be the start of my ASUs starts with the germ cell and the end of my ASUs ends with making these gametes either the sperm or the egg. And so what you can see here is that again, the process of my ASUs is right here. It starts with a deployed germ cell that has two copies of every chromosome and through the process of my oasis, which again is broken down into my ASUs one followed by psychokinesis and my ASUs two, followed by psychokinesis at the end of my oh sis noticed that we have four, uh gah meet cells that are going to be happy Lloyd represented by end and they're going to be genetically diverse. This cell would be genetically different from this one which is genetically different from this one and this one. And so again, through this image here on comparing it to the cell cycle that we talked about in our previous lesson videos, you could get a better feel for how my oh sis is going to be similar and yet still different from some of the cell cycle that we talked about previously and again, as we move forward in our courts, we're gonna talk mawr and more about my Oh, sis. So, uh, I'll see you all in our next video.
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Introduction to Meiosis Example 1

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already. So here we have an example problem that wants us to complete the sentence using one of these five potential answer options down below. And it says that the process of my oh sis produces an option. A notice says to diverse hap Lloyd game eat cells. Now, of course, from our last lesson video, we know that my oh sis is going to result in four cells not to sell. So any option that says two cells we know is going to be incorrect for my oh sis, so we can eliminate both Option A and Option B, which both mentioned two cells. And another thing that we can note is that my oh sis is going to create for genetically diverse cells that are not identical to each other. And so to say that it's going to create four identical cells is going to be incorrect and so we can eliminate both answer option C and answer option E because they both say identical. And so it turns out that option D is going to be the correct answer just through that logic there. And so my oasis ends up producing for genetically diverse cells that are Hap Lloyd Gam. It sells, meaning that they're going to be happy Lloyd, meaning that they're going to have half the number of chromosomes or just one copy of every chromosome and game meats, meaning that they're going to be sex cells, either sperm or egg. And so answer Option D is the correct answer to this example problem, and that concludes this example, so I'll see you all in our next video.
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Problem

Which of the following steps must occur before Meiosis I in germ cells?

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Meiosis I & Meiosis II

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So it turns out that my oh sis is actually broken down into two rounds of cell division, and the first round of Cell Division is my Asus one, and the second round of Cell division is my Asus two. And so in the first round of Cell division mitosis one, it's important to know that it's also sometimes referred to as reduction ALS division. And this is because my Asus one will reduce the ploy t of the cells, reducing a deployed cell into to Hap Lloyd cells. And it does this by separating homologous chromosomes from each other. And so you can see once again that in my oasis, one a deployed or to an germ cell is going to divide into two hap Lloyd daughter cells. And so the ploy he has been reduced because we've gone from a deployed cell into to Hap Lloyd cells. Now, the second round of cell division in my oh sis is my Asus two, which is sometimes referred to as equation a little division. And that's because my house is too maintains equal employee takes, taking to Hap Lloyd cells and forming four hap Lloyd cells so happy you start with Hap Lloyd cells and you end with Hap Lloyd cells. And so that maintains equal employees. And that's why it's called Equation all equal for equal. And so my Asus two maintains equal employees by separating Sister Chromatic kids instead of separating homologous chromosomes. So that's a big difference between my Oh sis one and My Asus two and again because my house is to is equation Aled division. It's gonna maintain equal employees. So you're going to start with the two Hap Lloyd cells from my oh sis one and those two Hap Lloyd cells from my oasis one are each going to divide to produce a total of four genetically diverse, still hap Lloyd gam. It's and so you started with happily. It sells and you still end with happily. It sells, and that's why it maintains equal employees. And so if we take a look at our image down below, it's another representation of my oh, Sis and Soe. Notice that before my Asus even begins, of course, Interphase is going to take place with the germ cell, which basically takes unwrap, hated chromosomes and forms, replicated chromosomes as we see here, and so this represent the germ cell, the deployed germ cell that, uh, is going to begin My, oh, sis. And again, my Oasis has really broken up into two rounds of cell division. The first round of cell division is my Oasis one, and so in my Oasis one, it's also referred to as reduction all division because it takes a deployed germ cell that is to end. And it divides the deploy germ cell into two cells. Daughter cells that air hap Lloyd or N. And then the second round of cell division is called my Asus two. And so my house is, too, is also sometimes referred to as equation Aled division because you start with Half Floyd cells and you also end with cells that are still hap Lloyd. And so it turns out that each of these cells is going to undergo my Asus two on a cell division to create a total of four Hap Lloyd game. It's and of course, the gametes are going to be the sex cells, either sperm and male or eggs and female. And so each of these phases of these stages of my oasis, my Oasis one and my Asus two, consists of multiple phases. And we're going to break down my Asus one and My Asus two in their own separate videos as we move forward in our course. But for now, this year concludes our introduction to my oh sis and how my Asus is really broken down into two rounds of Cell division and my Asus one and my Asus two. And so we'll be able to get some practice as we move forward in our course, and I'll see you all in our next video.
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Problem

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.

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Problem

In Meiosis II, ________ cells are divided into 4 ___________ daughter cells.

a) Diploid; Haploid.

b) Haploid; Diploid.

c) Haploid; Haploid.

d) Diploid; Diploid.

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