In somatic cells of oats 42 chromosomes. Determine the chromosome set and number of DNA molecules before the onset of meiosis I and in the metaphase of meiosis II. Answer explain
42 = 2n is a somatic cell, 21 = n is a gamete, n is the number of chromosomes, and s is the number of DNA molecules.
Before the onset of meiosis I, DNA replication (doubling) occurs in the interphase, the cell has a diploid set of chromosomes, but with doubled DNA – 2n4c, which means that the ovule cells during this period have 42 chromosomes and 84 DNA molecules.
At the end of meiosis I, a reduction division occurred (one chromosome from a pair of homologous chromosomes departed for each cell), after which each cell has a 1n2c chromosome set. In the metaphase of meiosis II, the chromosomes line up at the equator of the cell, the chromosome set does not change, which means that there are 21 chromosomes and 42 DNA molecules in the cells in this phase.
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