2B: creating sperm and egg 2D: fertilization creates new genetic combinations 2E: each parent contributes half of their DNA 2F: sex chromosomes determine sex

 I will be able to differentiate between gametogenesis and fertilization  I will be able to ___that half of my genes come from my ___; the other half come from my ___.  I will be able to ___that I am a new combination of my ___ and ___.  I will be able to ___that girls have ____chromosomes and boys have ___chromosome

Chromosome - linear DNA molecule Centromere - special region of spindle attachment Homologous Chromosomes Have the same kind of genes in the same order 1 from father, 1 from mother Sister chromatids (Blue, orange)

DNA Replication Chromatids Homologous Chromosomes A chromatid pair has an identical sequence of DNA

Mitosis 2N NNNN Meiosis Replicate Division Replicate Division

Produce 4 haploid gametes through - Interphase – replication of DNA - Meiosis I – separation of homologous chromosomes - Meiosis II – separation of sister chromatids Only occurs in ovary/testis

Differences between male and female Meiosis In Humans

 Half of the chromosomes from each parent.  Haploid-> Diploid  Genetic combination-> Variation  Zygote has a new combination ( new genes-> mutation)

Bb BB bB bb b b spermovum 4 Possible combinations BB, Bb and bB= brown eyes bb gives rise to blue eyes 4 possible combinations of genes: B B fertilization

 XX= female  XY = Male  Sperms determine the sex of the zygote  If the egg is fertilized by a sperm with an X chromosome, what will be the sex of the zygote?  A human male gets his X chromosome from _?

XXYY O XY OO XXYY XXYY XXOYY X XXY XO XXXXOXY Klinefelter’s Syndrome Klinefelter’s Syndrome Turner’s Syndrome Turner’s Syndrome Non-disjunction XY