Question

The amount of DNA in a G2 somatic cells is? (assuming the haploid cell of this organism is 3n)? a. 3n b. 12n C. 6n d. 1n e. On QUESTION 2 Which of the following statements about mammalian mitosis is NOT true? a. homologous chromosomes pair up at prophase b. daughter nuclei are genetically identical to the parent nucleus c. nuclear envelope breakdown coincides with onset of prometaphase d. onset of anaphase is inhibited until all chromosomes are aligned at the metaphase plate e. during prophase, each chromosome has two chromatids

Answer 1

Ans (c) : 6n ( As the G2 Phase of cell cycle comes after the completion of S phase of cell cycle & in S phase, the doubling of DNA content takes place during replication. As, the haploid DNA content is 3n , so in S phase the content will become 6n (3n * 2)& hence , the cells in G2 phase after the S phase will have 6n DNA content.

Ans (a) : homologous chromosomes pair up at prophase ( It is incorrect statement about mitosis, because the pairing of homologous chromosomes takes place in the prophase I (Zygotene stage) of meiosis I , so that recombination between homologous chromosomes can take place in pachytene stage of prophase I of meiosis I. This feature is absent in mitosis. Rest of the statements are true about mitosis.)

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