3.2 Understand that Fertilisation involves the fussion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo.
- Process begins with the adult male and female. The cells which make up an adult are described as "diploid" meaning it has a complete set of chromosomes which for humans is 46.
- In the male the cells are divided into sperm cells by meiosis which only has 23 chromosomes. Meiosis halves the number of chromosomes in the cell turning it from a diploid cell to a haploid cell. The same happens in the female cells.
- In sexual reproduction, these two cells are joined/fused together so that they form one cell. This process is known as Fertilisation which involves the combining of two haploid cells (23 chromosomes each) to form a new diploid cell with 46 chromosomes known as a "zygote". This new cell has the same number of chromosomes as any other regular adult, which is a combination of the male and female chromosomes.
- The newly formed Zygote now goes through a process called Mitosis. This is when the new cell divides to form two cells. Both cells will still have 46 chromosomes. These two cells would then divide again in the same way until their are sufficient cells for the structure to be called an embryo.
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