What Happens During Metaphase 2
Metaphase Definition
Metaphase is a phase of the cell cycle occurring in both mitosis and meiosis prison cell division processes. During metaphase in mitosis and meiosis, the chromosomes condense and they become visible and distinguishable during alignment at the center of the dividing cell, to form a metaphase plate at the center of the cell.
In this stage, a series of checkpoints take place ensuring the spindles are formed. In karyotyping studies, the metaphase stage is used to notice chromosomal abnormalities.
Paradigm Source: Ali Zifan (Wikipedia) and Ali Zifan (Wikipedia).
What happens in metaphase?
- Metaphase involves the separation of the duplicated genetic textile that is carried in the nucleus of the parent cells, to form two identical daughter cells.
- The process in metaphase involves the alignment of the chromosomes at the center of the cell by pulling and pushing, and what others would tern as a cellular tug of state of war.
- The replicated chromosomes remain joined at the centromere as sister chromatids.
- Before metaphase, the prophase stage formed radial microtubules known as kinetochores around the centrosome.
- The kinetochores are attached past long protein filament microtubules (kinetochore microtubules) that extend from the poles on either end of the cell.
- The kinetochore tubules pull the sister chromatids back and forth (tug of war) until an alignment at the equator of the jail cell is achieved. This forms an equatorial plane.
- Additionally, a metaphase checkpoint besides takes place during metaphase.
- The metaphase checkpoint that is known as the spindle associates checkpoint, ensures that the prison cell is ready to separate by checking the alignment of the chromosomes and the right attachment of the kinetochores.
- However the differences between mitosis and meiosis in the chromosome alignment, the spindle assembly checkpoint must take place during metaphase in both types of jail cell cycles.
- When these processes are correct, and so the prison cell enters the fourth phase of mitosis known as the anaphase.
Metaphase of Mitosis
Figure: Metaphase of Mitosis. Epitome Source: Ali Zifan (Wikipedia).
- Metaphase is a subsequent phase in the cell partition cycle that follows up from the condensation of the chromosomes from prophase.
- The condensation process is of import to ensure that the chromosomes (chromatids) exercise not get damaged during the pulling and pushing forces they undergo in metaphase.
- At the end of prophase or prometaphase, It is noted that the chromosomes are randomly arranged within the cell nucleus, inside a dissolved nuclear membrane.
- However, the polar and the radial microtubules are connected to each of the chromosomes.
- During mitosis, the microtubules from each of the centrosomes connect to each chromosome, which is fabricated upwards of two identical sister chromatids. The sister chromatids are connected past proteins known equally cohesins.
- The presence of microtubules allows the cell to exist a dynamic element in that they apply the forces of pulling and pushing.
- This is accomplished by the kinetochore microtubules, allowing the sister chromatids to get aligned at the center of the prison cell forming a metaphase plate.
- The subunit of these microtubules known as tubulin is added and removed constantly from the ends of the microtubules. This causes a treadmilling grade of movement of the microtubules and the sister chromatids.
- These treadmilling forces also contribute to the tight holding of the sis chromatids.
- The alignment of the chromatids along the metaphase plate ensures that the new cells that will be formed will exist identical.
- The chromatids must be attached to the microtubules from both poles of the cell and aligned at the metaphase plate for the spindle assembly checkpoint to have place.
- The checkpoint prolongs the period of metaphase, which can take days to ensure the chromosomes are properly aligned.
- Subsequently the checkpoint, the chromosomes release a signal activating the anaphase-promoting complex which leads to the finish of metaphase and the beginning of anaphase.
Metaphase of Mitosis Video Animation
Metaphase of Meiosis
Metaphase I in Meiosis
- During meiosis I the cells involved are coordinating, in that a diploid cell divides into haploid (half of the chromosomes).
- It works past involving chromosomal crossing over genes creating genetic variety in the girl cells of the next generation from the parent cells.
- Dna replication that takes place earlier meiosis forms the sister chromatids and therefore, during the meiosis I, the process starts with a homologous pair of each chromosome.
- The homologous pair is a representation of the same DNA simply has different alleles.
- The homologous pairs will adhere to each other during metaphase I and they undergo the alignment on the metaphase plate, different in mitosis where the sis chromatids are the ones that marshal on the metaphase plate.
- During this stage, a spindle checkpoint takes identify, otherwise known as the meiotic spindle checkpoint.
- This checkpoint ensures that the homologous pairs and each pair is attached to the kinetochore microtubules from each side of the cell before proceeding to the next phase which is anaphase I.
- Successful metaphase I ensure that meiosis Iproceed creating ii cells each with two copies of one-half of a total genome.
Figure: Metaphase one in Meiosis. Epitome Source: Ali Zifan (Wikipedia).
Metaphase I in Meiosis Video Animation
Metaphase 2 in Meiosis
- This is the second phase of meiosis 2.
- This is the phase where the two girl cells produced during the showtime meiotic partition, take their meiotic spindles start to draw the chromosomes to the metaphase plate, again.
- This is to set the centrosome for division in the next phase.
- Information technology takes place after a brusk break known as interkinesis.
- This initiates the cells to start dividing again, without any Dna replication taking place. Therefore, each jail cell volition have two copies of 1 allele for each cistron.
- Additionally, the nuclear envelope breaks downward as metaphase Two begins
- Even so, in this phase, the 2 kinetochores of each centromere volition bind to the spindle fibers from the opposite poles.
- This leads to a separation of the sister chromatids of each chromosome in the side by side stage.
- Also, a meiotic spindle checkpoint takes place during the separation of the chromatids for a swift move to the adjacent phase.
Effigy: Metaphase 2 in Meiosis. Epitome Source: Ali Zifan (Wikipedia).
Applications of Metaphase
- During the metaphase stage of cell partition, is when genetic abnormalities can be detected by karyotyping.
- This is because cross overs (meiosis) accept place during this phase and the pulling and pushing of the chromatids past the kinetochore microtubules may cause damages to the chromosomes if the mitotic spindle checkpoint and the meiotic spindle checkpoint are missed.
References and Sources
- https://world wide web.sparknotes.com/biological science/cellreproduction/mitosis/section2/
- https://www.britannica.com/scientific discipline/metaphase
- https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biological science/metaphase
- https://www.genome.gov/genetics-glossary/Metaphase
- https://www.nature.com/scitable/definition/metaphase-249/
- https://world wide web.nature.com/scitable/topicpage/mitosis-and-cell-partition-205/
- http://www.phschool.com/scientific discipline/biology_place/biocoach/meiosis/metai.html#:~:text=The%20centrioles%20are%20at%20opposite,poles%20called%20the%20metaphase%20plate.
- https://www.sciencedirect.com/scientific discipline/commodity/abs/pii/S0074769601120073
- https://www.biologyonline.com/dictionary/metaphase-two
- http://cyberbridge.mcb.harvard.edu/mitosis_6.html
- http://cyberbridge.mcb.harvard.edu/mitosis_7.html
- http://www.macroevolution.net/metaphase-ii.html
What Happens During Metaphase 2,
Source: https://thebiologynotes.com/metaphase/
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