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When in a hypotonic solution, water flows into the membrane and increases the cell's volume, while in an isotonic solution, water flows in and out of the cell at an equal rate. [4] Turgidity is the point at which the cell's membrane pushes against the cell wall, which is when turgor pressure is high. When the cell has low turgor pressure, it is ...
Chromosome segregation is the process in eukaryotes by which two sister chromatids formed as a consequence of DNA replication, or paired homologous chromosomes, separate from each other and migrate to opposite poles of the nucleus. This segregation process occurs during both mitosis and meiosis. Chromosome segregation also occurs in prokaryotes ...
The result of this spontaneous change in the structure of DNA is a so-called copy number variation. Due to the CNV chromosomes of different sizes can be combined in a new cell. If this occurs around conception, the result will be a first cell of a human with a genetic variation. This can be either positive or negative.
In genetics, a chiasma (pl.: chiasmata) is the point of contact, the physical link, between two (non-sister) chromatids belonging to homologous chromosomes. At a given chiasma, an exchange of genetic material can occur between both chromatids, what is called a chromosomal crossover, but this is much more frequent during meiosis than mitosis. [1]
Crossing over occurs between prophase I and metaphase I and is the process where two homologous non-sister chromatids pair up with each other and exchange different segments of genetic material to form two recombinant chromosome sister chromatids. It can also happen during mitotic division, [1] which may result in loss of heterozygosity.
The thick lines are chromosomes, and the thin blue lines are fibers pulling on the chromosomes and pushing the ends of the cell apart. The cell cycle in eukaryotes: I = Interphase, M = Mitosis, G 0 = Gap 0, G 1 = Gap 1, G 2 = Gap 2, S = Synthesis, G 3 = Gap 3. Cell division is the process by which a parent cell divides into two daughter cells. [1]
The proposal that chromosomes carried the factors of Mendelian inheritance was initially controversial, but in 1905 it gained strong support when Nettie Stevens showed that the "accessory chromosome" of mealworms' sperm cells was decisive in the sex identity of the progeny, [12] [13] a discovery supported by her mentor E.B. Wilson. [14]
Histogram showing how 20309 chromosomes adhere to Chargaff's second parity rule. The rule itself has consequences. In most bacterial genomes (which are generally 80–90% coding) genes are arranged in such a fashion that approximately 50% of the coding sequence lies on either strand.