[Campbell Biology P.656] According to Figure 28.19 b , which of the following is the correct... | Practice Question

According to Figure 28.19 b , which of the following is the correct sequence of nuclear events immediately following the initial partial fusion of two compatible Paramecium cells during conjugation?

  • A: Micronuclei undergo mitosis, then micronuclear fusion, then macronuclei disintegrate.
  • B: Diploid micronuclei undergo meiosis, three haploid micronuclei disintegrate, and the remaining micronucleus divides by mitosis.
  • C: Macronuclei fuse, then micronuclei divide by binary fission.
  • D: Cells swap macronuclei, then micronuclei undergo meiosis.

Explanation

According to steps 2 and 3 in Figure 28.19 b , after compatible cells fuse, 'Meiosis of micronuclei produces four haploid micronuclei in each cell.' Subsequently, 'Three micronuclei in each cell disintegrate. The remaining micronucleus in each cell divides by mitosis.' This accurately describes the sequence.