<P> In human fertilization , a release ovum ( a haploid secondary oocyte with replicate chromosome copies ) and a haploid sperm cell ( male gamete ) -- combine to form a single 2n diploid cell called the zygote . Once the single sperm enters the oocyte , it completes the division of the second meiosis forming a haploid daughter with only 23 chromosomes , almost all of the cytoplasm , and the sperm in its own pronucleus . The other product of meiosis is the second polar body with only chromosomes but no ability to replicate or survive . In the fertilized daughter , DNA is then replicated in the two separate pronuclei derived from the sperm and ovum , making the zygote 's chromosome number temporarily 4n diploid . After approximately 30 hours from the time of fertilization , fusion of the pronuclei and immediate mitotic division produce two 2n diploid daughter cells called blastomeres . </P>
<P> In human fertilization , a release ovum ( a haploid secondary oocyte with replicate chromosome copies ) and a haploid sperm cell ( male gamete ) -- combine to form a single 2n diploid cell called the zygote . Once the single sperm enters the oocyte , it completes the division of the second meiosis forming a haploid daughter with only 23 chromosomes , almost all of the cytoplasm , and the sperm in its own pronucleus . The other product of meiosis is the second polar body with only chromosomes but no ability to replicate or survive . In the fertilized daughter , DNA is then replicated in the two separate pronuclei derived from the sperm and ovum , making the zygote 's chromosome number temporarily 4n diploid . After approximately 30 hours from the time of fertilization , fusion of the pronuclei and immediate mitotic division produce two 2n diploid daughter cells called blastomeres . </P>
when does the fertilized ovum divide after fusion
when does the fertilized ovum divide after fusion
the zygote
the zygote