Name: cell division: mitosis and cytokinesis
Uploaded: 2023-06-23T15:38:45.000Z
Duration: 1 min 35 s
Channel: JoVE

Mitosis is a form of cell division where a cell&#39;s genetic material is partitioned between two daughter cells.&#160;
First, during prophase, nucleic chromatin condenses into x-shaped chromosomes composed of sister chromatid pairs attached at centromere junctions.
Concurrently, the centrosomes migrate to opposite cell sides. As they do so, microtubule rods begin to grow from each, forming a web-like spindle apparatus.
Next, the nuclear envelope dissolves during prometaphase and the protein structures, termed&#160; kinetochores, appear on both sides of the centromeres, one for every chromatin.
Once these kinetochores form, extending interior microtubules fasten to them, with each sister chromatid being tethered to a different cell pole.
In&#160; metaphase, the spindle apparatus rearranges the chromosomes so that they are oriented in a fixed row along the cell&#39;s equator.
With anaphase, kinetochore afixed microtubules shorten and sister chromatids are dragged apart. These and other microtubule dynamics also elongate the cell.
During telophase, the spindle apparatus disbands, chromatids loosen, and nuclear envelopes are reformed.
Finally, the cell is cytoplasmically divided by cytokinesis, forming a pair of cells genetically identical to their precursor.

mitosis and cytokinesis

Mitosis And Cytokinesis

In eukaryotes, the cell division cycle is divided into distinct, coordinated cellular processes that include cell growth, DNA replication/chromosome duplication, chromosome distribution to daughter cells, and finally, cell division. The cell cycle is tightly regulated by its regulatory systems as well as extracellular signals that affect cell proliferation.
The processes of the cell cycle occur over approximately 24 hours (in typical human cells) and in two major distinguishable stages. The first stage is DNA replication, during the S phase of interphase. The second stage is the mitotic (M) phase, which involves the separation of the duplicated chromosomes into two new nuclei (mitosis) and cytoplasmic division (cytokinesis). The two phases are separated by intervals (G1 and G2 gaps), during which the cell prepares for replication and division.
The Process of Mitosis
Mitosis can be divided into five distinct stages&#8212;prophase, prometaphase, metaphase, anaphase, and telophase. Cytokinesis, which begins during anaphase or telophase (depending on the cell), is part of the M phase but not part of mitosis.
Prophase
As the cell enters mitosis, its replicated chromosomes begin to condense and become visible as threadlike structures with the aid of proteins known as condensins. The mitotic spindle apparatus begins to form between the centrosomes&#8212;which were duplicated during the S phase&#8212;and migrate to opposite poles of the cell. The spindle is made up of filamentous structures called microtubules that are comprised of tubulin protein monomers. Spindle microtubules start extending towards the condensed chromosomes. The nucleolus, a component of the nucleus that produces ribosomes, vanishes, indicating the impending breakdown of the nucleus.
Prometaphase
During prometaphase, the microtubule filaments from the spindle apparatus continue to grow, and the chromosomes finish condensing. The nuclear envelope completely breaks down, releasing the chromosomes. Some of the microtubules attach to the released chromosomes, binding at a protein structure called the kinetochore that is present on the centromere of each pair of sister chromatids. Spindle microtubules from opposite poles attach to the kinetochores and capture the condensed sister chromatid pairs. Spindle microtubules that do not attach to chromosomes&#8212;polar and astral microtubules&#8212;help push the spindles apart and anchor the spindle poles to the cell membrane.
Metaphase
The spindle microtubules align each pair of the fully condensed sister chromatids along the equator of the cell&#8212;at the metaphase plate. The cell is now ready to divide.
Anaphase
The microtubules from opposite spindle poles, which are attached to the kinetochore structure, shorten and separate the sister chromatids at the centromere. The cohesion proteins that hold the chromatids together now break down. The shortening kinetochore microtubules cause each chromatid of the pair&#8212;now called chromosomes&#8212;to migrate to an opposite pole.
Telophase
Once the chromosomes reach opposite poles of the cell, they decondense and uncoil to form chromatin. The spindle microtubule filaments depolymerize into their tubulin monomers, which are then utilized as cytoskeletal elements in daughter cells. Nuclear envelopes reassemble around each set of chromosomes.
Cytokinesis
During cytokinesis in animal cells, actin filaments form a contractile ring in the plasma membrane to create a cleavage furrow, which eventually pinches the cell into two. In plant cells, vesicles from the Golgi apparatus carrying glucose, enzymes, and structural proteins join to form a new cell plate at the location of the former metaphase plate. The growing cell plate fuses with the plasma membranes on each side, eventually forming a new cell wall that divides the cell into two.
Mitosis is now complete, generating two daughter cells that are identical to the parent cell. In most human cells, mitosis accounts for about one hour of the approximately 24-hour cell cycle.

In eukaryotes, the cell division cycle is divided into distinct, coordinated cellular processes that include cell growth, DNA replication/chromosome ...

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Anatomy and Physiology

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Essential Cellular Processes

KEY TERMS AND CONCEPTS

cell division: mitosis and cytokinesis

Cell division depends on mitosis and cytokinesis. Mitosis is the stage when the cell’s nucleus divides and the copied chromosomes are separated into two sets. Cytokinesis is the step that follows and splits the cell into two daughter cells.

These two processes work together to make sure each new cell receives genetic material and its own cytoplasm. Mitosis keeps the chromosome sets organized, while cytokinesis finishes the division of the whole cell. Together, they create two separate cells from one starting cell.

Cell Division: Mitosis and Cytokinesis

the central dogma

Central Dogma: DNA to Protein

The central dogma explains how genetic information flows in cells from DNA to RNA to protein. It is a core idea in molecular biology and helps show how genes influence cell function. DNA stores the instructions. During transcription, a cell copies a gene into RNA, which is a related nucleic acid. That RNA message can then be used in translation to build a protein. Proteins carry out many jobs in cells and help determine traits. The central dogma links the genetic code in DNA to the molecules...

replication in eukaryotes

Eukaryotic DNA Copying at the Replication Fork

Eukaryotic DNA copying happens at replication forks, where the two DNA strands separate and new strands are built. This process lets a cell make an exact copy of its genetic material before it divides. The transcript explains that eukaryotic replication follows the same basic steps seen in other DNA replication systems, but it takes place in cells with a nucleus. The replication machinery works on each separated strand as a template, so the new DNA matches the original sequence. This topic is...

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RNA Types in Gene Expression

RNA types play different roles in gene expression. RNA, or ribonucleic acid, helps carry and use genetic information in cells. The main types discussed here are messenger RNA, ribosomal RNA, and transfer RNA. Messenger RNA, or mRNA, carries the genetic code from DNA to the ribosome. The ribosome is the site where proteins are made. Ribosomal RNA, or rRNA, is a key part of the ribosome itself. Transfer RNA, or tRNA, brings the correct amino acids to the ribosome during protein building. These...

transcription

Transcription and RNA Synthesis

Transcription is the process of making RNA from a DNA template. It is a key step in gene expression, because cells use the DNA sequence to build an RNA copy that can carry the message forward. During transcription, RNA polymerase binds to DNA and reads one strand as the template. The enzyme links RNA nucleotides together in the correct order to form a growing RNA molecule. This copying step does not make DNA; it produces RNA. The transcript focuses on the central idea of transcription as DNA...

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Translation: mRNA to Protein

Translation is the step in gene expression where ribosomes use messenger RNA, or mRNA, to build a protein. The mRNA sequence carries the instructions copied from DNA. During translation, those instructions are read in order so the cell can make a specific chain of amino acids. This process depends on the ribosome and transfer RNA, or tRNA. The ribosome reads the mRNA, and tRNA brings the matching amino acids. As the chain grows, the amino acids are linked together to form a polypeptide, which...

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Cell Cycle Stages in Cell Growth

The cell cycle is the process that controls cell growth and division. It explains how one cell makes two new cells. This process helps cells grow and reproduce.

interphase

Interphase and Cell Growth

Interphase is the part of the cell cycle when a cell grows and prepares to divide. It is a major stage of the cell cycle, and it comes before cell division begins. During interphase, the cell carries out its normal functions. It also copies its DNA so each new cell can receive a full set of genetic material. The cell may also build up the materials it needs for division. Interphase is not a single step. It includes phases such as G1, S, and G2, which help the cell grow, copy DNA, and get...

Cell division depends on mitosis and cytokinesis. Mitosis is the stage when the cell’s nucleus divides and the copied chromosomes are separated into two sets. Cytokinesis is the step that follows and splits the cell into two daughter cells. These two processes work together to make sure each new cell receives genetic material and its own cytoplasm. Mitosis keeps the chromosome sets organized, while cytokinesis finishes the division of the whole cell. Together, they create two separate cells...

the cell cycle control system

Cell Cycle Checkpoints and Cyclin Control

The cell cycle is controlled by checkpoints that help a cell move from one phase to the next and begin mitosis. This control system uses internal regulatory molecules and outside signals to send stop or advance instructions. It makes sure each step is finished before the cell moves forward. Cyclins and cyclin-dependent kinases, or Cdks, are the main regulators of the cell cycle. They act during the G1, G2, and M phases. These regulators work at specific checkpoints to keep cell division...

molecular factors affecting cell division

molecular-factors-affecting-cell-division

Cell Cycle Regulators That Control Division

Cell division is controlled by outside signals and by internal cell cycle regulators. Nearby cell death can encourage division, and human growth hormone (hGH) can also promote it. In contrast, too little hGH or crowded cells can slow or stop division. Inside the cell, regulator molecules help each stage finish correctly before the next stage begins. Some regulators act directly on the cycle, while others affect the activity or production of other regulatory proteins. These molecules can either...

what is meiosis?

Meiosis and the Formation of Gametes

Meiosis is the cell division process that forms gametes, or sex cells. It reduces the chromosome number so offspring can inherit the correct amount of genetic material. This process includes two successive divisions. First, one cell divides, and then the resulting cells divide again. These steps separate the genetic material in a controlled way. Meiosis helps explain how sexual reproduction passes traits from one generation to the next. It is a key topic in high school biology because it...

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Cell Signaling Pathways and Responses

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G Protein-coupled Receptor Signaling

G protein-coupled receptors are a major class of cell-surface receptors. They help cells detect signals outside the cell and pass that information inward. These receptors are important in many kinds of cell communication. When a signal binds to a G protein-coupled receptor, the receptor changes shape. That change activates a G protein inside the cell. The activated G protein can then start a signaling pathway. This signaling system includes the receptor, the G protein, and the downstream...

cellular differentiation

From Stem Cell to Specialized Cells

Cellular differentiation turns unspecialized cells into specialized cells with specific jobs. This process helps a complex organism, such as a human, develop from a single fertilized egg into a body with many cell types. Nerve cells, muscle cells, and epithelial cells are examples of the final cell types that appear during development. A zygote is the first cell after fertilization. It is a totipotent stem cell, which means it has very high differentiation potential and can form all cell types...

key terms and concepts

Learn how mitosis separates copied chromosomes and how cytokinesis divides the cell into two daughter cells in this high school biology page.

Cell Division: Mitosis and Cytokinesis | JoVE K12

anatomy and physiology

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

Cell Division: Mitosis and Cytokinesis

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