Scelta multipla
During which stage of meiosis does crossing over between homologous chromosomes occur?
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9. Mitosis and Meiosis
Meiosis
Scelta multipla
During meiosis, what happens to the chromosome number from the original diploid germ cell to the resulting gametes?
A
It doubles, producing tetraploid cells from a diploid cell.
B
It is reduced by half, producing haploid cells from a diploid cell.
C
It varies unpredictably because chromosomes segregate randomly into daughter cells.
D
It remains the same, producing diploid cells from a diploid cell.
Guida verificata passo dopo passo1
Step 1: Understand the starting point — a diploid germ cell contains two sets of chromosomes, one set inherited from each parent. This is represented as 2n, where n is the number of unique chromosomes.
Step 2: Recall the purpose of meiosis — it is a specialized cell division process that reduces the chromosome number by half to produce gametes (sperm or egg cells), ensuring genetic stability across generations.
Step 3: Recognize that meiosis consists of two consecutive divisions: meiosis I and meiosis II. During meiosis I, homologous chromosomes separate, reducing the chromosome number from diploid (2n) to haploid (n).
Step 4: During meiosis II, the sister chromatids separate, but the chromosome number remains haploid (n) because the chromatids are now individual chromosomes.
Step 5: Conclude that the chromosome number is reduced by half from the original diploid germ cell to the resulting haploid gametes, ensuring that when fertilization occurs, the diploid number is restored.
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