Difference Between Karyokinesis And Cytokinesis: Overview, FAQs
Mitosis are Meiosis are the types of cell division seen in organisms. Mitosis occurs in somatic cells, while Meiosis occurs in germinal cells. Mitosis and Meiosis are topics of the chapter Cell Cycle and Cell Division in Biology.
Definition of Karyokinesis and Cytokinesis
Mitosis is the concept that describes when a parent cell undergoes division to produce one or more daughter cells that contain genomes. It is a primary necessity for the growth, development, and reproductive activities of all the existing life forms. In mitosis, karyokinesis which is the division of the nucleus guarantees that the two daughter cells have an alike genetic material while cytokinesis which is the division of the cytoplasm of the cell splits the cellular contents to produce distinct cells. It creates new tissues and cells, repairs damaged ones and reproduces their kind, therefore making life and genetic reproduction go on in successive generations.
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Differences between Karyokinesis and Cytokinesis
The following draws the comparison between karyokinesis and cytokinesis
Aspect | Karyokinesis | Cytokinesis |
Definition and Process Comparison | Division of the nucleus during cell division. | Division of the cytoplasm and organelles to form two daughter cells. |
Timing within the Cell Cycle | Occurs during the M phase (mitosis or meiosis). | Follows immediately after karyokinesis, in the M phase. |
Mechanisms Involved | Involves processes like condensation of chromosomes, alignment at the metaphase plate, and separation of chromatids. | In animal cells, involves the formation of a cleavage furrow by contractile ring proteins (actin and myosin). In plant cells, involves the formation of a cell plate from Golgiderived vesicles. |
Structural Changes in the Cell | Chromosomes condense and align during metaphase; the nuclear envelope breaks down during anaphase. | Cell membrane or cell wall invaginates or forms between the two nuclei, dividing the cytoplasm and organelles into two separate daughter cells. |
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What is Karyokinesis?
Karyokinesis is a process through which a nucleus gets divided in the process of mitosis or meiosis to make two or more Daughter nuclei.
Phases of Karyokinesis
Prophase
Chromosomes condense and can be observed with light microscopy however, it is not recommended. There is discontinuity of the nuclear envelope, and spindle fibres develop.
Metaphase
Chromosomes align themselves in the middle of the developing cell wall, also called the metaphase plate. Spindle fibres connect to the kinetochores in the centromeres of every chromosome.
Anaphase
Sister chromatids begin to separate and move closer to the poles of the cell which is due to spindle fibers.
Telophase
Chromatids also get deposited to the poles and tend to decondense into chromatin. Membrane Lt a new nuclear envelope is formed for each set of chromosomes.
Significance of Karyokinesis in Cell Division
Karyokinesis guarantees that every daughter cell gets a full set and an identical copy of the genetic information. It preserves the genetic continuity between generations of cells, the growth and repair, as well as the division and reproduction of multicellular organisms.
What is Cytokinesis?
Cytokinesis is the last phase of cell division that results in the formation of two daughter cells each having its nucleus, from a single parental cell.
Process of Cytokinesis in different types of Cells
Cytokinesis in Animal Cells (Cleavage Furrow)
In animal cells, cytokinesis is distinguished by the formation of a cleavage furrow and this pinches the cell into two daughter cells.
Cytokinesis in Plant cells (Cell plate formation)
The plant cells in the process of cytokinesis initiate a cell plate at the equator of the dividing cell that later on differentiates into a new cell wall, which is found separating the daughter cells.
Significance of Cytokinesis in Cell Division
Cytokinesis makes certain that equal numbers of organelles and genes are passed from the parent cell to each daughter cell for growth, tissue repair in multicellular organisms, and reproduction. It preserves the shape of the cell and also helps in the transportation of necessary cellular components for the working of each new cell.
Biological Significance of Karyokinesis and Cytokinesis
The biological significance is discussed below:
Role in Growth and Development
Cytokinesis finalises the cell division to create two daughter cells that may further grow and develop tissues and/or organs.
Role in Tissue Repair and Regeneration
It aids in the renewal of our tissues because it is instrumental in the division of affected cells and the surmounting formation of new tissue layers.
Role in Reproduction (Mitosis vs. Meiosis)
In mitosis, cytokinesis splits the parent cell into two daughter cells which are required for growth and repair. During The meiosis process, cytokinesis occurs after both phases, and four genetically different haploid gametes are produced to enhance the process of sexual reproduction.
Common Errors and Anomalies
The errors are discussed below:
Examples of errors during Karyokinesis
Nondisjunction is another phenomenon that takes place when chromosomes do not segregate in the right manner when the cell is dividing. This may cause the formation of an unequal ratio of chromosomes in daughter cells that leads to genetic diseases, for example, down syndrome in human beings.
Examples of errors during Cytokinesis
Cytokinesis failure occurs when the cytoplasm and or some of the organelles do not divide to the middle and segregate into the daughter cells. This can lead to the formation of multinucleate cells or cells of sizes that are not normal which affects their performance and may cause diseases such as cancer.
Consequences of errors in Cell Division
Mistakes that occur in a cell division can sometimes cause cellular death or cancer and tumour formation that grows in the organism.
Mutations and faults caused by the mistakes in the staking of cells can also influence the general well-being and physiological efficiency of organisms, they can grow, expand, and reproduce improperly.
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Frequently Asked Questions (FAQs)
When karyokinesis takes place without cytokinesis, the outcome is the formation of a multinucleate cell or when more than one nucleus is located in the same cytoplasmic area. This process, called syncytium, is possible in some tissues due to the cells’ development or at stages of certain diseases.
In animal cells, cytokinesis involves the formation of cleavage furrows around the existing equator that divide the cell into two daughter cells. This process is initiated with the help of a contractile ring consisting of the actin filaments and myosin motor proteins.
On the other hand, the cytokinesis of plant cells involves a cell plate, which is made of a series of vesicles that include the cell wall material that consolidates at the middle of the dividing cell. In this method, the synthesis of a new cell wall is possible and grows between the two daughter cells.
Some of the important functions of microtubules are observed during the karyokinesis, which is the process of forming mitotic spindle – the apparatus that organises the chromosomes during the process of cell division.
Metaphase is characterised by the microtubules attaching themselves to the chromosomes at the kinetochore whereafter these are positioned at the center of the cell. At anaphase, the microtubules start to retract and this helps in the separation of the two sister chromatids to the two poles of the cell.
Karyokinesis is followed by cytokinesis because cytokinesis draws the process of cell division to a close by splitting the two newly formed daughter cells. If cytokinesis does not occur, instead of one nucleus in one cell, multiple nuclei will be in a cell disrupting the cellular organisation and functionality.
Correct cyokinesis lays the foundation for the creation of two individual daughter cells; genetically and in terms of their organelles; and is critical to the normal cellular physiological functions and tissue homeostasis.
Yes, mistakes in karyokinesis or cytokinesis can lead to cancer because cancerous cells split again and again. Any mishap at the microtubule level such as the chromosomal nondisjunction during karyokinesis can result in aneuploidy in the daughter cells.
Thus, when cytokinesis is improper or partial, the newly divided cell may be of different size than the parent cell and may contain more than one nucleus which is characteristic of cancer cells. Such mistakes can interfere with regular growth regulation activators, thus becoming a basis for the out-of-control proliferation of cells which is one of the hallmarks of cancer.
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09 Nov'24 08:49 AM