SBI 3U - Unit 2 Genetics

• Plants and animals grow by mitosis

• Plants and animals form gametes via meiosis

• Gametes are haploid (n) containing ½ the chromosomes

• Diploid zygote (2n) forms when male and female gamete fuse

• Formation of sex cells during meiosis is called GAMETOGENSIS

SBI 3U - Unit 2 Genetics

• Production of sex cells is similar YET different for human female and male

• Male process is called SPERMATOGENSIS

• One meiosis division produces four haploid sperm cells each with 23 chromosomes (humans)

• Males make billions of sperm cells per day

SBI 3U - Unit 2 Genetics

• Female process is called OOGENSIS

• Meiotic division produces only one haploid egg cell called an OVUM

• Three other cells, POLAR BODIES, contain all the genetic information of a haploid but lack enough cytoplasm to survive

• Unequal distribution of the cytoplasm is needed to fuel initial cell division in the event the egg cell is fertilized

• QUESTION – What happens to the polar bodies?