Thursday, September 15, 2011

3.2 Fertilisation

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

fertilization --> zygote --> embryo

1.  Process -
(Gametes are sex cells. The male gametes are the sperm, and the female gametes are the eggs.)

adult male  46 (diploid cell) --> (meiosis) --> half chromosome (number) set (Hoploid) --> Gametes 23

adult female 46 (diploid cell) --> (meiosis) --> half chromosome (number) set (Hoploid) --> Gametes 23

The cells that are formed by meiosis have half as many chromosomes as the cell that formed them.

2.  Fertilization occurs and the joining (fusion) of a male gamete and a female gamete. The new cell that is formed divides over and over again by meiosis. This creates the many cells that eventually form a new individual. Involves a half set of chromosomes (hoploid) + a half set of chromosomes (hoploid) = a diploid cell = Zygote

Stages of meiosis

chromosomes divide, similar chromosomes pair up, sections of DNA get swapped, pairs of chromosomes divide,  chromosomes divide

3. Fertilization complete --> new cell (combo of the male+female chromosomes) --> process of cell division (Mitosis) --> both contain 46 chromosomes --> each of these divide (still containing 46 chromosomes) --> embryo.

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