Understanding Mitosis - AP Biology

Metaphase is defined when chromosomes move towards the equator of the cell.

Other answers refer to other stages of mitosis. Sister chormatids separate during anaphase, two distinct cells form during telophase, centrioles move towards opposite poles of the cell during prophase, and DNA replication happens during interphase.

During anaphase, the third stage of mitosis, the spindle fibers cause sister chromatids to break apart, and they are subsequently moved to opposite sides of the cell.

Chromosomes condense during prophase, align during metaphase, separate during anaphase, and are relocated during telophase.

Chromatids condense during prophase, the first stage of mitosis. This allows the abundant amount of DNA to be organized into relatively small and tightly packed structures that can be aligned and separated later in mitosis. This also signifies the conversion of the DNA from loosely packed euchromatin to tightly packed heterochromatin.

Chromosomes condense during prophase, align during metaphase, separate during anaphase, and are relocated during telophase.

Cytokinesis, the process of the cytosol splitting into two daughter cells, occurs during telophase, the last phase of mitosis. Chromosomes line up at the metaphase plate during metaphase, while the nuclear membranes disappear and the nucleolus dissolve during prophase.

The chromosome will align along the center of the cell in metaphase, ready to be pulled apart into separate chromatids.

Mitosis begins in prophase, when chromosomes begin to condense and the nuclear envelope begins to dissolve. Chromosomes assemble at the equatorial plate during metaphase and are separated by spindle fibers during anaphase. During telophase, the chromosomes are enclosed in new nuclear envelopes. Finally, cytokinesis completes the division of the cell cytoplasm. Interphase refers to the portion of the cell cycle between mitotic divisions.

During anaphase the sister chromatids are pulled apart by the mitotic spindle and move to opposite ends of the cell. The nuclear membrane begins to break down at the very end prophase and is completely deteriorated during metaphase, when the chromosomes align. It is still fully formed during early prophase. The membrane begins to reconstruct during telophase, but is not fully intact again until cytokinesis.

The S phase, which is when the cell duplicates its DNA, and the G1 phase, during which the cell grows, are phases of the cell cycle that are not involved in mitosis, known as interphase. The nuclear membrane is only disrupted during mitosis, and is thus intact during all stages of interphase.

At metaphase the spindle microtubules that are attached to the kinetochores of the chromosomes move them to the metaphase plate, an imaginary structure at the midway point between the two poles of the cell.

During anaphase, the chromatids aligned on the equator of the cell are separated and pulled to opposite ends of the cell.

Prophase involves the condensation of chromatin into chromosomes and the removal of the nuclear envelope. The chromosomes align at the equatorial plate during metaphase and are pulled apart by the mitotic spindle fibers during anaphase. The chromatids begin to decondense during telophase, and the nuclear envelopes begin to form again.

The four mitotic stages included among these choices are prophase, metaphase, anaphase, and telophase, which occur in that order. The initial stage, prophase, involves chromosome condensation from chromatin and the formation of the spindle apparatus from microtubules. In metaphase, chromosome pairs line up in the center of the cell at a location called the metaphase plate. Anaphase involves the shortening of the microtubular spindle fibers, which forces chromosome pairs to migrate to opposite ends of the cell. Finally, telophase involves the formation of two new nuclei. Following telophase is cytokinesis, the final separation of the cytoplasm and other organelles of the two cells, and the sealing of the plasma membrane. Some references will include interphase, a period of rest, chromosome replication, and cellular checkpoints. Though not a part of mitosis itself, interphase separates successive mitotic divisions and acts as a time of cellular rest. In any case, the only properly matched definition above was that of telophase, the final stage of mitosis.

Mitosis is the process that results in two identical daughter cells. The separation of sister chromatids is essential to ensure that both daughter cells receive a copy of each chromosome. The maintenance of ploidy is a way of describing that the daughter cells will have the same number of each chromosome as the parent cells.

Crossing over, or recombination, is a process that only takes place during meiosis and helps promote genetic diversity.

When sister chromatids are still connected, they are only considered one chromosome. As soon as they separate, however, each sister chromatid is considered a chromosome.

Two chromatids in one chromosome: (X)

Two separated chromatids: (/\)

Because the question states immediately after the sister chromatids have separated, our yeast cells would have 24 chromosomes within the mitotic cell. Once mitosis is completed, each daughter cell would have 12 chromosomes. The question refers to a unique period during which all replicated genetic material is present within a single cell, but separated into fragments that constitute 24 total chromosomes.

Centromeres are the areas of chromosomes where sister chromatids are associated. They also have the important function of serving as the attachment site for microtubules of the mitotic spindle. Centromeres are not made of protein or microtubules.

Remember that a cell is defined as diploid if it possesses pairs of homologous chromosomes. During mitosis the cell always possesses homologous chromosomes. The segregation of chromosomes only involves the separation of sister chromatids to opposite sides of the cell, not the homologous chromosomes. The two daughter cells produced contain the same homologous pairs of chromosomes as the parent cell. A cell is therefore always diploid during mitosis and cytokinesis.

A cell will only become haploid during meiosis, when homologous chromosomes are separated during meiosis I and sister chromatids are separated during meiosis II.

Remember that the nuclear membrane is disassembled during prophase of mitosis. It remains absent through the duration of mitosis until it begins to reassemble during telophase. The nuclear membrane is thus absent during prophase, metaphase, and telophase.

The nuclear membrane is present (and essential) during all periods of interphase. The main functions of interphase are the synthesis of cellular proteins, DNA replication, and cellular growth. These processes require proper housing of the DNA and transport of mRNA across the nuclear membrane.

During mitosis we do not see separation of the homologous chromosomes. This is the reason that meiosis results in a reduction of ploidy and that mitosis does not. Separation of homologous chromosomes occurs after the formation of tetrads, during anaphase I of meiosis.

All of the other answers are processes that occur during both meiosis and mitosis. Both divisions require the condensation of chromosomes and eventual cytokinesis to produce daughter cells. Sister chromatids are separated during anaphase of mitosis, and during anaphase II of meiosis.

Anaphase is primarily characterized by the separation of the sister chromatids. This process occurs by degrading the protein securin, which binds the chromatids together. By degrading this protein, anaphase physically allows the sister chromatids to separate. Immediately after separation, the sister chromatids begin to migrate towards opposite ends of the spindle. Chromosome condensation occurs during prophase, not anaphase.

A chromosome carries the genetic material for a certain segment of the genome. A chromosome can consist of either one or two chromatids.

During metaphase, there are 46 chromosomes composed of two sister chromatids each that align at the metaphase plate. Then, during anaphase, these chromatids are separated and pulled to opposite poles of the cell. This separation results in 92 separate chromatids in the cell, which are considered 92 chromosomes.

Only germ cells will have 23 chromosomes. These haploid cells result from meiosis, rather than mitosis.

During telophase the chromosomes have been sufficiently separated, and new nuclei can be formed. Telophase functions to prepare the cell for cytokinesis be sealing the chromosomes off from the cytoplasm in a new nuclear envelope.

The nuclear envelope first dissolves during prophase, allowing the chromosomes to migrate into the cytoplasm. They align at the center of the cell during metaphase. Sister chromatids are separated during anaphase, and the cell prepares for the final stages of division during telophase.

During metaphase, chromosomes line up along the center of the cell. At this point, each chromosome contains two sister chromatids.

During anaphase, sister chromatids are separated but remain within the same cell cytoplasm.

A chromosome can consist of either one or two chromatid. A single chromatid is considered a chromosome once it has been separated from its pair. During anaphase, each of the cell's 46 chromosomes is split into singular chromatids, and each chromatid is considered a separate chromosome structure for a total of 92 chromosomes. Once the cell completes division, these chromatids are sequestered into separate nuclei and the cell returns to its normal diploid state.