AP Biology Meiosis Part 1 Interphase MITOSIS MEIOSIS

AP Biology Meiosis Part 1

Interphase

. MITOSIS MEIOSIS Parent cell (before chromosome replication) Chiasma (site of crossing over) MEIOSIS I Propase Prophase I Chromosome replication Duplicated chromosome (two sister chromatids) Chromosome replication 2 n = 6 Chromosomes positioned at the metaphase plate Metaphase Anaphase Telophase Sister chromatids separate during anaphase 2 n Tetrad formed by synapsis of homologous chromosomes Tetrads positioned at the metaphase plate Homologues separate during anaphase I; sister chromatids remain together Metaphase I Anaphase I Telophase I Haploid n=3 Daughter cells of meiosis I 2 n MEIOSIS II Daughter cells of mitosis n n n Daughter cells of meiosis II Sister chromatids separate during anaphase II n

Parent to offspring

Mom and Dad’s DNA contribution The egg surrounded by sperm.

Locus (Gene locations on chromosomes)

Asexual reproduction (One parent) See the bud on the side… that is the “new” organism to be.

Sexual Reproduction (Two parents)

Lifecycles of organisms Key Haploid Diploid n Gametes n Mitosis n MEIOSIS Haploid multicellular organism (gametophyte) n FERTILIZATION Diploid multicellular organism Animals Zygote 2 n Mitosis n Spores Gametes MEIOSIS 2 n n Haploid multicellular organism 2 n Diploid multicellular organism (sporophyte) Mitosis n n Gametes n FERTILIZATION MEIOSIS 2 n Mitosis Plants and some algae Zygote FERTILIZATION 2 n Zygote Most fungi and some protists

Female (XX) Karyotype (Remember… “kary” means “nucleus”)

Male (XY) Karyotype

Germ cells at fertilization