The randomness in the alignment of recombined chromosomes at the metaphase plate, coupled with the crossing over events between nonsister chromatids, are responsible for much of the genetic variation in the offspring. To clarify this further, remember that the homologous chromosomes of a sexually reproducing organism are originally inherited as two separate sets, one from each parent. Using humans as an example, one set of 23 chromosomes is present in the egg donated by the mother. The father provides the other set of 23 chromosomes in the sperm that fertilizes the egg. Every cell of the multicellular offspring has copies of the original two sets of homologous chromosomes. In prophase I of meiosis, the homologous chromosomes form the tetrads. In metaphase I, these pairs line up at the midway point between the two poles of the cell to form the metaphase plate. Because there is an equal chance that a microtubule fiber will encounter a maternally or paternally inherited chromosome, the arrangement of the tetrads at the metaphase plate is random. Thus, any maternally inherited chromosome may face either pole. Likewise, any paternally inherited chromosome may also face either pole. The orientation of each tetrad is independent of the orientation of the other 22 tetrads.
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The Pacific Plate moves northwestward past the North American Plate along the San Andreas.
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The correct answer is 4,960,000
Explanation:
If a yeast cell divides into two yeast cells in 120 minutes that means a yeast cell needs 2 hours to get double. So according to the question 2 hours ago a yeast colony consisted of 310,000 cells that means the present colony should have 620,000 cells.
So after six hours from now, this population will divide three times in six hours because the generation time of yeast cell is 2 hour and each time the number of cells will double.
Therefore, in first time the number will increase to 1,240,000(620000*2), the second time the number will increase to 2,480,000(1240000*2) and after final division, the number will be 4,960,000(2480000*2).
Therefore after 6 hours from now, the approximate number of yeast cells will be 4,960,000.
