3.2 Fertilisation

Notes


Fertilisation = "fusion of male and female gamete to produce a zygote that undergoes cell division and develops into an embryo"

1. In both Adult male & Adult female:
-> Each is in terms of a Diploid (2n) (diploid = complete set of chromosomes, 46)
-> Diploids divide in testis to produce gametes (meiosis = sperm and egg)
    -> Diploid (2n) / 2 = Haploid (n)
    -> 23 per sperm/egg

2. Fertilisation = two cells are fused together (Sperm gamete & egg gamete) to form ONE CELL

In human:
-> Haploid (n = 23) + Haploid (n = 23) => Diploid (2n = 46) =  new cell known as ZYGOTE
-> Zygote combination of male and female cells but same no. of cells as adult human

3. Mitosis = cell divides (1-2-4-8-16, etc.), 2n -- mitosis --> 2n ALL CELLS CONTAIN DIPLOID (2n = 46) NUMBER OF CHROMOSOMES
-> Embryo = large collection of diploid cells

*Note: process is true for all sexually reproducing animals, variance in no. of chromosomes