In mammals, the nuclei resulting from the union of the sperm and the egg are first truly diploid at the end of the
A) acrosomal reaction.
B) completion of spermatogenesis.
C) initial cleavage.
D) activation of the egg.
E) completion of gastrulation.

Question

Quizplus · Accepted Answer

The initial cleavage of the zygote leads to the first truly diploid nuclei in mammals. Prior to this, the sperm and egg nuclei are haploid. The acrosomal reaction and activation of the egg occur before fertilization and do not lead to diploid nuclei. Spermatogenesis occurs in the male prior to fertilization and does not directly affect the nuclei of the zygote. Gastrulation occurs after the formation of the diploid nuclei.

In Mammals, the Nuclei Resulting from the Union of the Sperm