4.3: Mitotic Cell Division- Division of the Nucleus (Mitosis) + Division of the Cytoplasm (Cytokinesis)
- Page ID
- 53561
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Mitotic Cell Division - Division of the Nucleus (Mitosis) + Division of the Cytoplasm (Cytokinesis)
Human cells divide for embryonic development, growth of the human, injury repair, tumor and cancer development and spread, cell regeneration, and cell differentiation by a process called mitotic cell division. The word "mitotic" in "mitotic cell division" refers to the fact that mitosis, division of the nucleus, is a part of the entire cell division process. After mitosis is complete, the cell is still a single cell, but now the DNA has been divided into two nuclei, with each nucleus containing a set of DNA (chromatids) identical to the other nucleus. Producing genetically identical nuclei is possible because the cell separates the sister chromatids from each other during mitosis and packages one chromatid of each pair of identical sister chromatids into a separate nucleus.
Mitotic cell division is only complete after the cell completely divides into two cells. After mitosis is complete, the cell with two nuclei undergoes cytokinesis to divide the cytoplasm, thereby completing mitotic cell division.
Cells proceeding through the steps of mitotic cell division have a lot going on. DNA condenses at the beginning and decondenses at the end, the nucleus breaks down and then reforms as two nuclei, sister chromatids are separated into two separate nuclei, the chromatids are moved around, organized, and pulled apart by microtubules, and the entire cell splits in a way that 1 nucleus ends up in each daughter cell. To better understand and describe the phases of mitotic cell division, mitosis is broken up into the following phases:
- prophase
- prometaphase
- metaphase
- anaphase
- telophase
Cells leaving the G2 phase of the cell cycle enter prophase first, the first stage of mitosis. The last phase of mitosis is telophase where the cell contains two separate nuclei. Cytokinesis follows telophase to create two separate cells. Examine the table below to investigate the appearance of a cell in each phase of mitosis and the major events occurring in each phase. Pay special attention to the chromatids through this process (shown as orange/red Xs representing sister chromatids, as single red lines in anaphase representing single chromatids, and as orange dots in prophase and telophase representing decondensed DNA) as well as the nuclear envelope (shown as a dark green circle - when this line is dashed it indicates the envelope is either breaking down or forming), the microtubules aka mitotic spindle (shown as blue lines) that move chromatids around the cell, and centrosomes (shown as a pair of orange rectangles) that organize the microtubules:
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Phase of Mitosis |
Major Events of this Phase |
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prophase
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prometaphase
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metaphase
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anaphase
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telophase
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After telophase is complete, mitosis is complete since the nucleus has now divided into two identical nuclei. Cytokinesis follows the end of mitosis to complete mitotic cell division:
|
Phase of Mitotic Cell Division |
Major Events of this Phase |
|---|---|
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cytokinesis
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Although the events of mitotic cell division are separated into phases, it is analogous to breaking up an entire day into morning, afternoon, evening, and night - it is all a part of the same day, but we describe the parts differently. As such mitotic cell division is a fluid process where one stage evolves into the next. To see an animation of how mitotic cell division proceeds in a cell, watch this video.
The length of the cell cycle is highly variable, even within the cells of a single organism. In humans, the frequency of cell turnover ranges from a few hours in early embryonic development, to an average of two to five days for epithelial cells, and to an entire human lifetime spent in G0 by specialized cells, such as cortical neurons or cardiac muscle cells. There is also variation in the time that a cell spends in each phase of the cell cycle. When fast-dividing mammalian cells are grown in culture (outside the body under optimal growing conditions), the length of the cycle is about 24 hours. In rapidly dividing human cells with a 24-hour cell cycle, the G1 phase lasts approximately nine hours, the S phase lasts 10 hours, the G2 phase lasts about four and one-half hours, and the M phase lasts approximately one-half hour. In early embryos of fruit flies, the cell cycle is completed in about eight minutes. The timing of events in the cell cycle is controlled by mechanisms that are both internal and external to the cell.
Attributions
- "BIOL 250 Human Anatomy Lab Manual SU 19" by Yancy Aquino, Skyline College is licensed under CC BY-NC-SA 4.0
- "Biology 2e" by Mary Ann Clark, Matthew Douglas, Jung Choi, OpenStax is licensed under CC BY-NC 4.0
- "Mitotic Prophase" by LadyofHats is in the Public Domain
- "Mitotic Prometaphase" by LadyofHats is in the Public Domain
- "Mitotic Metaphase" by LadyofHats is in the Public Domain
- "Mitotic Anaphase" by LadyofHats is in the Public Domain
- "Mitotic Telophase" by LadyofHats is in the Public Domain
- "Mitotic Cytokinesis" by LadyofHats is in the Public Domain