Where does my DNA Come From?
A new organism is produced from two parent cells Sexual Reproduction A new organism is produced from two parent cells
Types of organisms that reproduce sexually
Sex Cell A cell involved in sexual reproduction It has 1/2 the number of chromosomes as a normal cell (n) Example: human sex cells have 23 chromosomes, the rest of the human cells have 46 (2n)
Egg The female sex cell Made in ovaries
Sperm Male sex cell of an animal Made in testes
Pollen Male sex cell of a plant
Fertilization The fusion or combining sex cells such as egg and sperm
Zygote The fertilized cell formed during sexual reproduction
Meiosis A type of cell division which creates sex cells that have ½ the number of chromosomes
2n 4n Meiosis I 2n 2n Meiosis II n n n n