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Time-lapse video of mitosis in a Drosophila melanogaster embryo. The primary result of mitosis and cytokinesis is the transfer of a parent cell's genome into two daughter cells. The genome is composed of a number of chromosomes—complexes of tightly coiled DNA that contain genetic information vital for proper cell function. [32]
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
In mitosis, the sister chromatids separate into the daughter cells, but are now referred to as chromosomes (rather than chromatids) much in the way that one child is not referred to as a single twin. Schematic karyogram of a human, showing a diploid set of chromosomes as seen in the G 0 and G 1 phases of the cell cycle (before DNA synthesis ...
In eukaryotes, there are two distinct types of cell division: a vegetative division , producing daughter cells genetically identical to the parent cell, and a cell division that produces haploid gametes for sexual reproduction , reducing the number of chromosomes from two of each type in the diploid parent cell to one of each type in the ...
This process results in each gamete usually containing a mixture of chromosomes from both original parents. Improper chromosome segregation (see non-disjunction, disomy) can result in aneuploid gametes having either too few or too many chromosomes. The second stage at which segregation occurs during meiosis is prophase II (see meiosis diagram ...
The process by which cells divide into two daughter cells is called mitosis. Once these cells are formed they enter G1, the phase in which many of the proteins needed to replicate DNA are made. After G1, the cells enter S phase during which the DNA is replicated.
A cell during anaphase. Microtubules are visible in green. Stages of late M phase in a vertebrate cell. Anaphase (from Ancient Greek ἀνα-() 'back, backward' and φάσις (phásis) 'appearance') is the stage of mitosis after the process of metaphase, when replicated chromosomes are split and the newly-copied chromosomes (daughter chromatids) are moved to opposite poles of the cell.
Arresting mitosis in metaphase by a solution of colchicine; Squashing the preparation on the slide forcing the chromosomes into a single plane; Cutting up a photomicrograph and arranging the result into an indisputable karyogram. The work took place in 1955, and was published in 1956. The karyotype of humans includes only 46 chromosomes.