- Written By: J.Gunsch
- Edited By: Sara Z. Potter
- Last Modified Date: 30 January 2012
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2003-2012 Conjecture Corporation
Mitosis is the scientific term for nuclear cell division, where the nucleus of the cell divides, resulting in two sets of identical chromosomes. Mitosis is accompanied by cytokinesis in which the end result is two completely separate cells called daughter cells. There are four phases of mitosis: prophase, metaphase, anaphase and telophase.
The first phase of mitosis is prophase. In this phase the chromosomes which are normally spread throughout the nucleus begin to condense into a tight ball. The DNA molecules of the chromosomes begin to interact with enzymes and proteins that assist in the replication of the genes. The compact coiling of the chromosomes at this stage of mitosis is called mitotic chromosomes. Nearing the end of prophase, the material enclosing the nucleus and the cytoskeleton disappears. The cytoskeleton is transformed into what is called a spindle apparatus which works to pull the duplicated chromosomes apart during the anaphase.
The second phase of mitosis is metaphase. In this phase the chromosomes of the dividing cell begin to line up and are coordinated with the spindle apparatus. The soon to be divided chromosomes are symmetrically positioned on the metaphase plate typically at the equator of the parent cell.
Anaphase is the third step of mitosis. Abruptly the spindle apparatus pulls the two identical sets of chromosomes apart from one another. Each new set of chromosomes is moved to opposite spindle poles. These two sets of chromosomes will soon develop into the nuclei of two daughter cells perfectly identical to each other as well as identical to the parent cell.
The final stage of mitosis is telophase which means end. Telophase is best described as the opposite of prophase. As the chromosomes begin to move toward the spindle pole they start to uncoil and spread out. Then the spindle apparatus made of the former cytoskeleton is deconstructed. Finally the nuclear envelope or membrane is formed around the chromosomes. Although this is the last phase of mitosis, telophase will not be complete until cytokinesis has been carried out. Cytokinesis is similar to mitosis except it involves the cell’s cytoplasm and organelles where mitosis is the division of the nucleus or control center of the cell. Once mitosis and cytokinesis are properly completed there are two new functioning cells.
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anon176544
Post 39 |
There is only four stages as it is debatable whether interphase is actually a stage because in interphase its pretty much just a carry on from cytokinesis and the actual cellular division does not begin until anaphase. |
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Enayatullah Naseri
Post 37 |
what is the difference between mitosis and meiosis? |
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anon126774
Post 36 |
actually if you look at that picture of the cell cycle (the one with the arrows going around in a the circle) Interphase is one big cycle with 3 phases 1. G1 2. Chromosomes Duplication 3. G2 And lastly, it's Mitosis with four stages. 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase And after Mitosis is Cytokinesis. Cell division is not completed until Cytokinesis is finished. Then it starts back over at Interphase going through its three cycles. So basically, everybody is wrong, besides that first comment. |
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anon118206
Post 35 |
There are three stages to the cell cycle: interphase, mitosis, and cytokinesis. Each stage can be further subdivided in to smaller phases. Interphase is the stage where the cell grows and but it is not actually a part of mitosis because the genetic material is actively carrying out the 'job' of the cell. The end of interphase is signaled by the visibility of the cell's DNA which indicates that the first state of mitosis has begun. Mitosis is typically divided in to four basic phases: prophase, metaphase, anaphase, and telophase which will be discussed below since that was the focus of the original question. Cytokinesis is the final stage of the cell's life and involves 'pinching off' the cell membrane (not to be confused with 'pinching off' the nuclear membrane during the last part of mitosis). The key distinction between mitosis and cytokinesis is that mitosis refers to the duplication and division of the cell's nucleus and cytokinesis refers to the final division of the cell itself. Cytokinesis is not part of mitosis because it involves the division of the cell membrane and the cell's other organelles - but not the nucleus. Now, back to mitosis, the second stage of the cell's life cycle. The four 'major' phases of mitosis are prophase, metaphase, anaphase, and telophase. Keep in mind that mitosis refers to the duplication and division of the nucleus and only the nucleus. Each term is used to indicate the position of the chromosomes and condition of the nuclear membrane during mitosis. Prophase: chromosomes become visible and uncoil, Metaphase: chromosomes are lined up along the 'equator' of the cell by spindles from the centrosomes and the nuclear membrane begins to thin and disappear, Anaphase: the nuclear membrane is completely dissolved and the doubled chromosomes are 'pulled apart' towards opposite ends of the cell by the spindles. Telophase: each set of chromosomes is surrounded by a new nuclear membrane and two identical nuclei now exist. The confusion here seems to revolve around the further division of the four stages of mitosis into five or six or even more distinct phases. Prometaphase simply refers to the stage of mitosis where the nucleus is at the very end of prophase and the very beginning of metaphase. The chromosomes don't just 'jump' from the middle of the cell to the opposite ends of the cell (although it does happen extremely fast) but it's still a progression from one position to the next. Imagine creating a flip-cartoon of mitosis – you would have to draw the chromosomes at progressively further and further points away in order to see the motion when you flipped the pages (this is a good exercise to do if you’re having trouble visualizing all of this). Combining the four basic phases merely serves to more accurately describe the actual location of the chromosomes and the condition of the nuclear membrane at a specific time. If you've learned the four basic phases then you've also, by default, learned the more specific phases as well. If you know what the nucleus looks like in prophase and you know what the nucleus looks like in metaphase - then prometaphase is halfway between the two. Just to reiterate: interphase and cytokinesis are not parts of mitosis, they are distinct and completely separate parts of the cell's life cycle. |
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anon114404
Post 32 |
There are five phases. |
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anon91152
Post 29 |
there are only four and that's the correct answer. |
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anon83833
Post 26 |
Taking college level intro to biology now and they are teaching five phases: interphase, prophase, metaphase, anaphase and telophase. |
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greycloud
Post 25 |
what is the preparatory phase in mitosis? |
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anon66718
Post 24 |
is there a process in which it tells about the chromosomes steps anywhere? |
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anon65966
Post 22 |
There are four basic phases in mitosis: Prophase, Metaphase, Anaphase and Telophase. Interphase represents the non-dividing stage of a cell's life when it fulfills its specialized function. During this time a cell is quite busy growing, synthesizing proteins, organelles and replicating DNA in preparation for the next round of cell division or mitosis. Interphase is definitely *not* part of mitosis. Some teachers do not make this distinction very clearly. However, interphase is part of the cell's life cycle (cell cycle) so this is where people are getting confused. |
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anon61283
Post 20 |
there are actually five stages of mitosis: metaphase prophase anaphase and telephase. |
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anon55848
Post 18 |
There is 6 stages: G2 of Interphase, prophase, prometaphase, metaphase, anaphase and telophase and cytokinesis. |
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anon54783
Post 17 |
interphase is not considered one because of the g1 s and g2. |
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anon53617
Post 16 |
Actually I think that there are only four stages in mitosis. The prophase (divided into early and late prophase); the metaphase; the anaphase (divided into early and late anaphase); and the telophase.
The interphase isn't part of mitosis but actually part of the cell cycle. In the interphase the g1, s and g2 phase are included. |
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anon51374
Post 12 |
Doesn't matter there's four or five stages or not, I've got to study everything involved in cell division for the test! |
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anon50876
Post 11 |
there are actually eight: interphase, prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis and then back to interphase. |
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anon48147
Post 7 |
There are actually 5 stages of mitosis. Interphase is part of the cell cycle, but precedes mitosis. The 5 stages are: 1. Prophase 2. Prometaphase 3. Metaphase 4. Anaphase 5. Telophase Cytokinesis is also part of the cell cycle, but this is not part of mitosis. This is part of the interphase. |
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anon47002
Post 6 |
yes there are five stages: the interphase, metaphase, anaphase, telophase and phrophase. i even know that and i'm very young and still in middle school. |
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anon29242
Post 5 |
7 stages to be more precise. 1. Interphase(Assumed to be resting but the most active and longest period of mitosis) 2. Prophase 3. Prometaphase( This stage is actually said to be in prophase but for understanding the concept of prophase better this stage is in mitosis too.) 4. Metaphase( Shortest period,) 5. Annaphase( Chromosomes are pulled apart) 6. Telephase 7. Cytokenesis( Division of cytoplasm) |
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anon26331
Post 4 |
Interphase has an affect, but is not actually a part of mitosis. |
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anon22751
Post 3 |
anon18908: there are four phases. not five. |
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anon18908
Post 2 |
there is actually 5 stages of mitosis: interphase metaphase prophase anaphase and telephase. |
