Phases of Mitosis - Video Tutorials & Practice Problems

Phases of Mitosis

in this video, we're going to introduce the phases of my toe. Sis and SOE recall from our previous lesson videos that my toe sis is an a sexual process because it only involves one single parent cell. And so my toes is is the a sexual process that's defined as the division of the nucleus. So it's going to divide the nucleus and the genetic material of the cell, and that sells specifically going to be a somatic cell or ah, body cell, which is a cell that is not passed down from generation to generation, and it stays within the same multi cellular organism. Now, my toe sis is going to start with one single deployed cell that has two copies of every chromosome, and it's going to end with two genetically identical deployed cells. So not only does it start with a deployed cell, but it also ends with deployed cells and these two cells that are deployed they are genetically identical to each other, and again, this is what makes my toasts and a sexual process. Now this line right here that's highlighted in Green is going to be a very key line toe. Understand my toe, sis. And to distinguish might assis from my oh, sis, when we cover my Asus later on in our course. So, uh, this is a line that you really want to make sure that you have, uh, committed to your memory. Now my toes is turns out that actually consists of five different phases that we have number down below. And so this image that you see down below right here represents my toe sis, and within my toast is there are five phases. The first is pro phase. Then there's pro meta phase meta phase and a phase and tell a phase. And so notice that might assist ends with a single cell. So notice that the cell is still technically connected. But this single cell has two nuclei. So, really, it's just division of the nucleus. You start with one nucleus, and it ends with two nuclei. And really, that is what mitosis is defined as it's defined as the division of the nucleus and the genetic material in a somatic body cell. And so, my toe sis, the division of the nucleus, is going to be followed up by another process called psychokinesis, which we'll talk about later in our course, which is gonna be division of the Cytoplasm, and it will end up separating the the cell here in half so that each daughter cell ends up having their own nucleus. And so, as we move forward in our course, we're going to talk about each of these individual stages of my toe sis and the most important events that take place during each of these phases. And so this year concludes our introduction to the phases of my toasts. And again we'll get to talk Maura about each of these phases as we move forward. So I'll see you all in our next video.

How to Remember the Order of the Phases of Mitosis

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. a) Prophase - prometaphase - anaphase - metaphase – telophase.
• B. b) Prophase - prometaphase - metaphase - anaphase – telophase.
• C. c) Prometaphase - prophase - metaphase - anaphase – telophase.
• D. d) Metaphase - anaphase - interphase - prophase – telophase

Prophase

so the very first phase of mitosis is pro phase, and during pro phase, they're going to be very specific events that occur. And one of those events is that the loosely coiled chroma tint that exists during interphase is going to condense to form very distinct chromosomes. And these chromosomes are going to have sister chromatic IDs that air linked at the Centrum ear position and recall the central Mir is not to be confused with the central zone. The Central mirror is going to be the waste position of the chromosomes, where the Sister Crowe motives are linked together and the central zone is going to be the formation, the structure that forms the my tonic spindle. Now, in addition to the DNA changing its confirmation from chroma tin, two distinct chromosomes. Uh, the nuclear Olis, which is recall from our previous lesson videos the location of rivals own synthesis and recall the nuclear. Is this structure within the nucleus itself? Um, it's actually going to disappear from the nucleus and so really ride. His own synthesis is going to stop. It's going to come to a halt, then the third and final event that's going to take place is the two central zones again. Centrism not to be confused with Central Mirror. The central zones which are going to form the mighty Dick spindle, are going to migrate to opposite poles. They're going to migrate to opposite poles within the cell, and they're going to begin forming the might. Ah, tick spindle and the my tonic spindle Recall our thes micro tubules proteins that are responsible for moving the DNA around during my toe, sis. And so the metallic spindle is beginning to form during pro fees. And so notice down below, in our image, we're showing you all of the phases of my toes is here pro fes, pro meta phase meta phase and phase and tell a phase. And so here we're focusing specifically on pro fes and noticed that, uh, pro phases, uh, cells that are just exiting the G two phase of interphase are going to be entering into the very first phase of my toasts, which is pro phase. And during pro phase. We have the very specific events that occur here in the middle. So what's going to happen is the loosely coiled crow Metin condenses to form distinct chromosomes essentially distinct chromosomes air going to form. That's the first event. Also, the nuclear Olis is going to disappear. The new CLee old us is going to disappear. And so notice that the nuclear Olis is this blue. This structure that you see here within the nucleus notice that it is no longer found over here during pro fates because it disappears and also noticed that the my tonic spindle is going to form when these two Sentras OEMs they move to opposite poles of the cell. So notice there's one central zone here. The other central zone is here and there, uh, essentially forming the MIT Todd ICS spindle and again the central zones. What you see here and here are not to be confused with the Centrum ears, which recalled The central mirrors are the waste positions here of the chromosomes where the two Sister Crowe motives are formed. And so really, this concludes the events of pro phase here and after pro fes recall is pro meta phase. So we'll talk about pro meta phase in the specific events that occurred there in our next video. So I'll see you all there

Prometaphase

so after pro phase, the second phase of mitosis is pro meta phase. Now it's important to note that in some of your textbooks pro meta phases also sometimes referred to as late pro Fes and so in some of your textbooks, they won't even mention pro meta phase as a phase. Instead, they'll just batch all of the events of pro meta phase into pro fes, because again, sometimes pro meta phase is referred to as late pro phase. So that's important to keep in mind. If your textbook does not have a pro meta phase phase in it, then that means that your textbook is just batch ing the events of pro meta phase with pro phase the phase that comes right before. Now there are really two specific events that they're going to take place during pro meta phase. That's important for you all to know. The first is that the nuclear envelope or the nucleus itself is going to degrade or, in other words, break down. And so when the nuclear envelope degrades or breaks down, it's actually going to expose the chromosomes to the cytoplasm. And that means that the might, ah, tick spindle that has been forming is capable of linking to the chromosomes by attaching to specific proteins called kinetic core proteins that air found within the Centrum ear of the chromosomes. Recall the Centrum ear, which is not to be confused with the, uh, central zone. The central here is the waste position of the chromosomes where the two sister chromatic IDs are going to meet, and so notice down below again, in our image, we're showing you the full all of the stages of mitosis. But we're not focusing on these over here were specifically focusing on the second phase of my toes is pro meta phase. And so notice on the left we're showing you the first phase pro phase and the image that we talked about in our last lesson video. And in this video, we're talking about pro meta phase, which is this image right here. And the events that are taking place are right here in the middle. And so the first thing that's going to happen is the nuclear envelope is going to degrade or break down. In other words, and so you can see over here in pro fes, the nucleus is intact. But over here in pro meta phase notice that the nuclear envelope has been broken down. It's degrading, which is why we're showing it in these small pieces. And so that is going to expose the chromosomes to the cytoplasm of the cell and that allows the might Arctic spindle to attach to these kinetic or proteins that air found, uh, in the Centrum ears of the chromosome. And so again, the Centrum ear is going to be the waste position. So right here in these positions of the chromosomes, you'll find these little green proteins that are the kinetic core proteins. And this is where the micro tubules of the my Tadic spindle can attach. And when these micro tubules attached to the kinetic core is, they can move the chromosomes around. And that's what we're going to see is going to happen in the next phase. And so this here concludes pro meta phase, and in our next phase of my toast is we're gonna talk about meta phase itself, so I'll see you all in that video

The phase of mitosis where chromosomes condense and centrosomes move to opposite poles of the cell is:

• A. Prometaphase
• B. Metaphase
• C. Prophase
• D. Anaphase
• E. Telophase

Why does the nuclear envelope break down during prometaphase?

• A. To allow the chromosomes to condense.
• B. To allow the sister chromatids to form
• C. To allow the mitotic spindle to form.
• D. To allow spindle fibers to attach to chromosomes.

Metaphase

Yeah. And so the third phase of my toast, this is metaphysics. A's and meta phase is pretty easy to remember because you can think that the M and meta phase is for the M in the word metal. And so, during meta phase, the my topic spindles air going to align the chromosomes in the middle of the cell in a single file road. And so the equator or the middle of the cell is referred to as the meta phase plate. And so if we take a look at our image down below, of course, we're showing you the phases of my toes is And we've already covered pro fes and pro meta phase in our previous lesson videos. And so here in this video, we're focusing specifically on meta phase, which you can see the image of meta phases over here on the right and the events that occurred during meta phase air here in the middle. And so, of course, when you're thinking about meta phase, you want to think about how this M here is going to remind you of the M and the word metal. And so the chromosomes are going to a line in the middle of the cell on the meta phase plate. And so notice that the chromosomes here are lining up in a single file row right here in the middle of the cell. Now, the fact that the chromosomes are aligning in a single row is actually going to be very important here because later, in our course, when we're talking about my oh, sis, we'll see that in some scenarios of my oh, sis, the chromosomes are not going to align in a single foul row, and instead they're going to align in two rows on DSO. The fact that during my toast is aligns in a single road is going to be important to keep in mind. Now this here concludes our introduction to metaphysics. And of course, after meta phase is the fourth phase and a phase. So we'll talk about that in our next video

The mitotic spindle plays a critical role in which of the following processes of cellular division?

• A. Splitting the cytoplasm following mitosis.
• B. Triggering the condensation of chromosomes.
• C. Dissolving the nuclear membrane.
• D. Moving the chromosomes within the cell.

Which of the following events characterizes metaphase of mitosis?

I. Movement of chromosomes to the equatorial plane (metaphase plate) of the cell.

II. A spindle fiber attaches to each sister chromatid.

III. Separation of sister chromatids that are being pulled to the poles of the cell.

• A. I.
• B. II.
• C. III.
• D. I and II.
• E. All of these

Metaphase is characterized by ________.

• A. Separation of the sister chromatids.
• B. Separation of the cytoplasm.
• C. Alignment of chromosomes along the cell's equator.
• D. Alignment of the mitotic spindle along the cell's equator.

Anaphase

And so the fourth phase of mitosis is Anna phase and Anna phases also kind of easy to remember because you can think that the A in an A phase is for the A in the word apart. And so, during an a phase, the sister Chromatis, they're going to get pulled apart towards opposite ends of the cell, essentially starting to separate the DNA so that each daughter cell can get their own copy of the DNA. So during an a phase, some parts of the my Tadic spindle are going to shorten in orderto pull chromatic IDs apart from each other. But in other scenarios, uh, the my Tadic spindle will lengthen. And when the my Tadic spindle lengthens, that's actually going to stretch the cell, allowing the cell to start Thio divide. And so if we take a look at our image down below again, we're showing you all of the phases of my toasts. And already in our previous lesson videos, we've covered pro fes, pro meta phase and meta phase as well. And so here in this video we're focusing on the fourth phase and phase, which the image for Anna phases over here on the far right and the events of Anna phase air here in the middle. And so, of course, when you're thinking about Anna phase, you think about how the A and an A phase represents the A and the word apart. And so the Sister Crowe motives are going to get pulled apart from one another. And so notice here that in meta phase, the chromosomes, which are replicated chromosomes, are aligned here in the middle on the meta phase plate. And during Anna phase noticed that the sister Chromatic kids are getting pulled apart from one another. And so, essentially, you can see that these, uh, this sister cremated is getting pulled in this direction. This sister chromatic is getting pulled into this direction. Uh, this one here is getting pulled in this direction, and this one here is getting pulled in this direction over here. And so the sister chromatic, they're getting pulled apart from one another. But notice that other, uh, parts of the my topic spindle are actually lengthening. And so these parts that air lengthening, getting longer, they're actually pull pushing the cell and stretching the sell out. And so that is going to Ah essentially facilitate the division of the cell as well. And so this year concludes our introduction to Anna phase and how the sister Chromatic get pulled apart and and our final phase of my toes is we'll talk about tell a phase in our next video, so I'll see you all there.

In what way do kinetochore microtubules facilitate the process of splitting the sister chromatids?

• A. a) They use motor proteins to hydrolyze the centromere at specific arginine residues.
• B. They create tension by pulling toward opposite poles.
• C. They slide past each other like actin microfilaments.
• D. They phosphorylate the centromere, thereby changing its conformation.

Which of the following is a function of the non-kinetochore microtubules?

• A. Maintaining an appropriate spacing among the moving chromosomes.
• B. Starting the separation of the cytoplasm once the final stage of mitosis is complete.
• C. Providing the ATP needed by the kinetochore microtubules to move the chromosomes.
• D. Pulling the poles of the cell closer together.
• E. Pushing the poles of the cell further apart.

Telophase

And so the fifth and final phase of mitosis is tell a phase and recall. You could think that the T in tele phases for the T entail end and hopefully that will help you remember that tele phases the final phase of mitosis. And so again, the final step of my toes is is tell a phase, and it turns out that the final step of my toes is tell a phase is. Actually it's practically the opposite or the reverse of pro fes and pro meta phase. And so, if you can remember pro fes and pro meta phase, then you already know the events that take place in tele phase because again they're practically the opposite or the reverse. And so recall that in pro fes, the loosely coiled crow metin would condense into tightly coiled chromosomes. But here in tel, a phase, it's the tightly coiled chromosomes that began to revert back to the loosely coiled crow Metin State and recall that during pro fes and pro meta phase, the my tonic spindle would begin to form. But here in tel, a phase, the my tonic spindle is going to degrade or break down, and then also, of course, recall from our previous lesson videos that during pro fes and pro meta phase, the Nuclear Solis and the nuclear envelope would degrade or disappear breakdown. Whereas here in tel, a phase the reverse is happening. The nuclear olis and nuclear envelope are going to reform and they're going to reform at each end of the cell in order to form two nuclei. And ultimately that is the conclusion of mitosis taking one nucleus and separating the DNA to form two nuclei. And so let's take a look at our image down below here, which again is showing you all of the phases of my toe, sis. And already in our previous lesson videos, we've covered pro fes pro meta phase meta phase and Anna phase. And so here in this video we're focusing on Tele phase, whose images over here on the right and of course, the events of tele phase air Here in the middle and again, the events of telephones are pretty much the complete opposite or reverse of pro fes and pro meta phase. And so what's going to happen is the chromosomes are going to begin to unwind back into the crow Metin state. Uh, the nuclear Solis is going to reform. The nuclear envelope is also going to reform, and ultimately they're going to be two nuclei that air formed at each end of the cell and the my topic spindle is also broken down so you can see that the my tonic spindle is no longer there. The nucleus has reformed at each end of the cell. The nucleus Olis, which is the structure here for ride. His own synthesis has also reformed, and the chromosomes have begun to unwind into their crow. Metin state. And so really, this here concludes our introduction to tell a phase and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.

The nuclear envelopes form and the mitotic spindles disassembles during telophase in preparation for what?

• A. The merging of the two nuclei.
• B. The division of the cell into two daughter cells, each with their own nuclei.
• C. The division of the cell into four daughter cells, each with half a nuclei.
• D. Nothing, the cell now possesses two nuclei and twice the amount of genetic material.

The circles labeled A to E each represent the chromosomes within a cell during a single phase of mitosis. Which image is showing one of the newly created nuclei at the end of telophase?

• A. A
• B. B
• C. C
• D. D
• E. E

At which phase of the cell cycle do centrosomes begin to move apart in animal cells?

• A. Anaphase
• B. Metaphase
• C. Telophase
• D. Prophase

Scientists isolate cells in various phases of the cell cycle. They isolate a group of cells that have 1 1/2 times more DNA than G1 phase cells. What is the most likely part of the cell cycle from which these cells were isolated?

• A. between the G1 and S phases in the cell cycle.
• B. in the G2 phase of the cell cycle.
• C. in the M phase of the cell cycle.
• D. in the S phase of the cell cycle.

If there are 40 centromeres in a cell at anaphase of mitosis, how many chromosomes will be found in each daughter cell following cytokinesis?

a) 10.

b) 20.

c) 40.

d) 80.

• A. 10.
• B. 20.
• C. 40.
• D. 80.

Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol prevents microtubule depolymerization (breaking down). Thus, Taxol stops mitosis by interfering with which of the following structures or processes?

a) The mitotic spindle.

b) Cytokinesis.

c) DNA replication.

d) Chromosome condensation.

• A. The mitotic spindle.
• B. Cytokinesis.
• C. DNA replication.
• D. Chromosome condensation.