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What does it mean when a cell enters anaphase before all of its chromosomes have attached to the spindle?
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∙ 12y ago
This indicates that the cell is not responding to the internal regulators inside the cell.
Wiki User
∙ 12y ago
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What would happen if one or more spindle fibers failed to form from one spindle apparatus?
Since spindle fibers are involved in separating chromosomes and centrosomes duringmitosis, you would have impaired mitosis. The spindle is largely made of organized microtubules, which help chromosomes line up during metaphase and then separate during anaphase. The cell has many "checkpoints" which will check to make sure that chromosomes are properly lined up and attached before they can be separated. If the spindle fibers are not properly formed, it would be harder to get past the checkpoint, and so mitosis would be delayed or would not occur at all. If there are mutations in checkpoint proteins (such as in cancer cells), mitosis may proceed but the chromosomes may not be separated normally (resulting in "aneuploidy").They would die because spindle fibers isn't for indiviuals itz mostly dealing with the different phases of mitosis
How many chromosomes does new cells have at the end of the cycle?
Anaphase 1: Before Meiosis begins, each chromosome is duplicated, like in Mitosis. When the cell is ready for meiosis, each duplicated chromosome is visible under the microscope as two Chromatids. Anaphase 2:The two cells formed during Meioses 1 now begin Meiosis 2. The chromatids of each duplicated chromosome will be separated during this division. (Anaphase also means Meiosis. Meiosis 1 and Meiosis 2 for instance. i hoped this helped!)
What is the change in chromosome number in meiosis?
The Reduction of Chromosome Number in Meiosis Is Determined by Properties Built into the Chromosomes. In meiosis I, two chromatids move to each spindle pole. Then, in meiosis II, the two are distributed, one to each future gamete. This requires that meiosis I chromosomes attach to the spindle differently than meiosis II chromosomes and that they regulate chromosome cohesion differently. We investigated whether the information that dictates the division type of the chromosome comes from the whole cell, the spindle, or the chromosome itself. Also, we determined when chromosomes can switch from meiosis I behavior to meiosis II behavior. We used a micromanipulation needle to fuse grasshopper spermatocytes in meiosis I to spermatocytes in meiosis II, and to move chromosomes from one spindle to the other. Chromosomes placed on spindles of a different meiotic division always behaved as they would have on their native spindle; e.g., a meiosis I chromosome attached to a meiosis II spindle in its normal fashion and sister chromatids moved together to the same spindle pole. We also showed that meiosis I chromosomes become competent meiosis II chromosomes in anaphase of meiosis I, but not before. The patterns for attachment to the spindle and regulation of cohesion are built into the chromosome itself. These results suggest that regulation of chromosome cohesion may be linked to differences in the arrangement of kinetochores in the two meiotic divisions.
What is a biorientation?
A biorientation is an orientation of chromosomes to opposite poles of the bipolar spindle before cell division.
What are the four phases of mitosis and explain what occurs during each phase?
The first stage of mitosis is the interphase where the nucleous is defined and two centrosomes are formed. The next phase is the prophase when the nucleoli disappear. During the metaphase the centromes are at opposite ends of the cell poles. During anaphase paired chromosomes separate. The final stage is the telophase where the cell splits into two cells.
When do the spindle fibers shorten?
Spindle fibers shorten during anaphase I and anaphase II in meiosis in order for both the separation of the homologous chromosomes and the sister chromatids to opposite poles before telophase I and II. After cytokinesis, the end result would be four daughter cells, otherwise known as the tetrad, being produced with half the number of chromosomes as compared to the parent cell. In mitosis, spindle fibers attached to the kinetochores of the chromosome shorten only during anaphase to separate the sister chromatids away from the centromere to opposite poles in preparation for cytokinesis where there would be a cleavage furrow deepening at the equator of the cell. The end result of mitosis are two daughter cells with identical number of chromosomes as the parent cell.
What would happen if one or more spindle fibers failed to form from one spindle apparatus?
Since spindle fibers are involved in separating chromosomes and centrosomes duringmitosis, you would have impaired mitosis. The spindle is largely made of organized microtubules, which help chromosomes line up during metaphase and then separate during anaphase. The cell has many "checkpoints" which will check to make sure that chromosomes are properly lined up and attached before they can be separated. If the spindle fibers are not properly formed, it would be harder to get past the checkpoint, and so mitosis would be delayed or would not occur at all. If there are mutations in checkpoint proteins (such as in cancer cells), mitosis may proceed but the chromosomes may not be separated normally (resulting in "aneuploidy").They would die because spindle fibers isn't for indiviuals itz mostly dealing with the different phases of mitosis
How many chromosomes does new cells have at the end of the cycle?
Anaphase 1: Before Meiosis begins, each chromosome is duplicated, like in Mitosis. When the cell is ready for meiosis, each duplicated chromosome is visible under the microscope as two Chromatids. Anaphase 2:The two cells formed during Meioses 1 now begin Meiosis 2. The chromatids of each duplicated chromosome will be separated during this division. (Anaphase also means Meiosis. Meiosis 1 and Meiosis 2 for instance. i hoped this helped!)
What is the relationship between chromosomes and chromatids?
Chromosomes are the condensed and replicated form of DNA. The two identical halves of the chromosomes are known as sister chromatids. Before division, while the chromatids are still attached, they form one chromosome. However, when anaphase (i.e the stage when chromosomes split) starts and they are separated, the two chromatids on the opposite poles of the cell become complete chromosomes.
During which phase of mitosis do the paired chromatids break apart at the centromere to become individual chromosomes before moving toward opposite poles of the cell?
Anaphase!! :)
What happens during metaphase stage?
At metaphase, the nucleus has completely degraded and the chromosomes are all ligned up at the centre of the cell. This line up of chromosomes is called the metaphasic plate. During metaphase, the chromosomes are maximally condensed.
What is the change in chromosome number in meiosis?
The Reduction of Chromosome Number in Meiosis Is Determined by Properties Built into the Chromosomes. In meiosis I, two chromatids move to each spindle pole. Then, in meiosis II, the two are distributed, one to each future gamete. This requires that meiosis I chromosomes attach to the spindle differently than meiosis II chromosomes and that they regulate chromosome cohesion differently. We investigated whether the information that dictates the division type of the chromosome comes from the whole cell, the spindle, or the chromosome itself. Also, we determined when chromosomes can switch from meiosis I behavior to meiosis II behavior. We used a micromanipulation needle to fuse grasshopper spermatocytes in meiosis I to spermatocytes in meiosis II, and to move chromosomes from one spindle to the other. Chromosomes placed on spindles of a different meiotic division always behaved as they would have on their native spindle; e.g., a meiosis I chromosome attached to a meiosis II spindle in its normal fashion and sister chromatids moved together to the same spindle pole. We also showed that meiosis I chromosomes become competent meiosis II chromosomes in anaphase of meiosis I, but not before. The patterns for attachment to the spindle and regulation of cohesion are built into the chromosome itself. These results suggest that regulation of chromosome cohesion may be linked to differences in the arrangement of kinetochores in the two meiotic divisions.
What is a biorientation?
A biorientation is an orientation of chromosomes to opposite poles of the bipolar spindle before cell division.
What are the four phases of mitosis and explain what occurs during each phase?
The first stage of mitosis is the interphase where the nucleous is defined and two centrosomes are formed. The next phase is the prophase when the nucleoli disappear. During the metaphase the centromes are at opposite ends of the cell poles. During anaphase paired chromosomes separate. The final stage is the telophase where the cell splits into two cells.
What are the types of cells in meiosis?
Meiotic divisions The two meiotic divisions may be divided into a number of distinct stages. Meiotic prophase refers to the period after the last cycle of DNA replication, during which time homologous chromosomes pair and recombine. The end of prophase is signaled by the breakdown of the nuclear envelope, and the association of the paired chromosomes with the meiotic spindle. The spindle is made up of microtubules that, with associated motor proteins, mediate chromosome movement. In some cases (such as human sperm formation), the spindle is already formed at the point of nuclear envelope breakdown, and the chromosomes then attach to it. In other systems (such as human female meiosis), the chromosomes themselves organize the spindle. Metaphase I is the period before the first division during which pairs of interlocked homologous chromosomes, called bivalents, line up on the middle of the meiotic spindle. The chromosomes are primarily (but not exclusively) attached to the spindle by their centromeres such that the centromere of one homolog is attached to spindle fibers emanating from one pole, and the centromere of its partner is attached to spindle fibers from the other pole (see illustration). The bivalents are physically held together by structures referred to as chiasmata that are the result of meiotic recombination events. In most meiotic systems, meiosis will not continue until all of the homolog pairs are properly oriented at the middle of the spindle, the metaphase plate. The orientation of each pair of homologs on the spindle occurs in a random fashion, such that the paternally derived homolog of one bivalent may point toward one pole of the spindle, while in the adjacent bivalent the maternally derived homolog is oriented toward the same pole.
What is mitosis 4 stages?
The four stages of Mitosis are Prophase, Metaphase, Anaphase, Telophase1. InterphaseDNA has replicated, but has not formed the condensed structure of chromosome. They remain as loosely coiled chromatin.The nuclear membrane is still intact to protect the DNA molecules from undergoing mutation.2. ProphaseThe DNA molecules progressively shorten and condense by coiling, to form chromosomes. The nuclear membrane and nucleolus are no longer visible.The spindle apparatus has migrate to opposite poles of the cell..3. MetaphaseThe spindle fibres attach themselves to the centromeres of the chromosomes and align the the chromosomes at the equatorial plate.4. AnaphaseThe spindle fibres shorten and the centromere splits, separated sister chromatids are pulled along behind the centromeres.　4. TelophaseThe chromosomes reach the poles of their respective spindles. Nuclear envelope reform before the chromosomes uncoil. The spindle fibres disintegrate.î“â€
What are the three stages if cell cycle?
There are many different stages in mitosis. They are(in order): Interphase, Prophase, Metaphase, Anaphase, Telephase, and Cytokinesis.Their functions:DNA has replicated, but has not formed the condensed structure of chromosome. They remain as loosely coiled chromatin.The nuclear membrane is still intact to protect the DNA molecules from undergoing mutation.1. ProphaseThe DNA molecules progressively shorten and condense by coiling, to form chromosomes. The nuclear membrane and nucleolus are no longer visible.The spindle apparatus has migrate to opposite poles of the cell..2. MetaphaseThe spindle fibres attach themselves to the centromeres of the chromosomes and align the the chromosomes at the equatorial plate.3. AnaphaseThe spindle fibres shorten and the centromere splits, separated sister chromatids are pulled along behind the centromeres.4. TelophaseThe chromosomes reach the poles of their respective spindles. Nuclear envelope reform before the chromosomes uncoil. The spindle fibres disintegrate.After these, the cell just begins to split completely in half.
