3.2- Fertilisation

Understand that fertilisation involves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo

• The cells in testis and in ovaries have a complete cell of chromosomes and this is called diploid (2n) which is a complete set of chromosomes and for human it is 46
• The cells divide to form cells with half sets of chromosomes, this type of cell division is called meiosis this makes the cell go from a diploid number to a haploid number(n) which is a 1/2 set so in humans it is 23
• During sexual reproduction the two cells are brought together and joined together, so it forms just 1 cell. This process is know as fertilization and it involves the combining of half set of chromosomes and another half set of chromosomes to make a full set of chromosomes (23+23=46)
• This cell is known as a Zygote
• This cell goes through Mitosis in which the cells divide but they all contain 46 chromosomes
• It will be called an embryo when we have sufficient amount of cells