MEIOSIS NOTES 11 4 MEIOSIS NOTES 11 4

MEIOSIS NOTES (11. 4)

(MEIOSIS NOTES 11. 4) REPRODUCTION Asexual- all of the parent DNA goes to offspring (mi. Tosismain. Tains) Sexual -used to create

2 TYPES OF CELLS 1) BODY CELLS 2) SEX CELLS

BODY CELLS -All cells other than sex cells -Also called somatic cells -Made by mitosis

BODY CELLS -Contain 2 copies of each chromosome -homologous chromosomes -have diploid #, 2 n EX. Humans =46

SEX CELLS -Gametes -Eggs and sperm -Made by meiosis -Have haploid #, n -EX. Humans =23

HOW DO WE GET 46 CHROMOSOMES? Egg (haploid #) + Sperm(haploid #) ZYGOTE (diploid #) Ex. Humans

MEIOSIS SEX CELLS m. Eiosis = r. Eduction division -starts with 1 diploid cell and ends up with 4 haploid cells **Meiosis I and Meiosis II

MEIOSIS I

MEIOSIS II

MEIOSIS DIAGRAM

CROSSING OVER Occurs during Prophase I of meiosis Tetrads form and DNA is exchanged XX ADVANTAGE: genetic variation

CROSSING OVER Adapted from: Morgan T. H. , Sturtevant A. H. , Muller H. J. , and Bridges C. B. , "The Mechansim of Mendelian Heredity", 1915.

EGG FORMATION (UNEQUAL CYTOKINESIS)

COMPARING MITOSIS AND MEIOSIS HOW MANY CELLS ARE MADE? Mitosis 2 Meiosis 4

COMPARING MITOSIS AND MEIOSIS ARE RESULTING CELLS GENETICALLY THE SAME OR DIFFERENT? Mitosis. Genetically the same Meiosis Genetically different

COMPARING MITOSIS AND MEIOSIS WHAT TYPES OF CELLS RESULT IN THE PROCESS? (BODY CELLS OR GAMETES) Mitosis = Body cells Meiosis = Gametes

COMPARING MITOSIS AND MEIOSIS WHAT ARE THE ADVANTAGES OF EACH PROCESS? Mitosis. Growth and repair Meiosis. Formation of sex cells and genetic variation