Announcements Test Corrections: 12/6 – 12/16 Take Biospheres Home

p. 329 A.Q. 1ab, 3a & p. 327 Analyzing Data 1, 4 Question of the Day Question: What is mitosis and what does it create? Answer: … … … More than 25 types of elements 3’s Turn In: p. 329 A.Q. 1ab, 3a & p. 327 Analyzing Data 1, 4

Biosphere Report: Part 2 More than 25 types of elements

Meiosis Notes & Vocabulary Sheet

Before Mitosis: Phases of Mitosis: Interphase Prophase Metaphase Anaphase Telophase Interphase Prophase Metaphase Anaphase Telophase

Unit 5 Vocabulary meiosis- cell divisions resulting in 4 unique cells with half of the normal number of chromosomes 19. mitosis- cell division resulting in 2 identical cells

Introduction Meiosis is a type of cell division that makes cells with half the number of chromosomes How 1N gametes (sex cells) are created http://www.youtube.com/watch?v=C8OL1MTbGpU

Unit 5 Vocabulary diploid (2n)- 2 sets of chromosomes 17. haploid (1n)- 1 set of chromosomes

Introduction Meiosis creates genetic diversity through the recombination of chromosomes DNA is replicated during interphase beforehand In meiosis, the cell will divide twice to make four 1N cells http://www.youtube.com/watch?v=C8OL1MTbGpU

Prophase I Meiosis I DNA coils into chromosomes Spindle fibers appear Homologous chromosomes pair together, forming a tetrad http://www.youtube.com/watch?v=C8OL1MTbGpU

Unit 5 Vocabulary 24. homologs (homologous chromosomes)- a pair of corresponding chromosomes, 1 from each parent 25. tetrad- a pair of duplicated homologous chromosomes

Meiosis I Prophase I Portions of chromatids may break off and attach to adjacent chromosomes; this is called crossing-over Crossing-over exchanges genetic material between maternal and paternal chromosomes http://www.youtube.com/watch?v=C8OL1MTbGpU 20. crossing over- sections of chromatids are broken off and exchanged

Metaphase I Meiosis I Spindle fibers attach Tetrads line up in middle of cell http://www.youtube.com/watch?v=C8OL1MTbGpU

Meiosis I Anaphase I Homologous chromosomes are pulled apart to opposite ends of the cell Which homologous chromosome goes to which end is random http://www.youtube.com/watch?v=C8OL1MTbGpU

Telophase I Meiosis I Cytokinesis occurs, forming two 1N cells http://www.youtube.com/watch?v=C8OL1MTbGpU

Meiosis II Prophase II Spindle fibers appear

Meiosis II Metaphase II Chromosomes move toward middle of the cell

Meiosis II Anaphase II Chromatids separate, pulled to opposite ends of each cell

Telophase II Meiosis II Cytokinesis occurs again Four 1N cells are formed

Formation of Gametes Sperm and eggs are produced through meiosis makes 4 sperm in testes makes 1 ovum (egg) and 3 polar bodies in ovaries http://www.youtube.com/watch?v=C8OL1MTbGpU

Unit 5 Vocabulary 9. ovum (ova)- a female sex cell or egg 10. sperm- a male sex cell 8. gamete- sex cells (ex: sperm or ovum) 7. somatic/body cell- a cell in an organism not used in sexual reproduction

Meiosis vs. Mitosis Lab

Mitosis Meiosis A process of cell division DNA is replicated in prophase Produces 2 identical cells Produces diploid cells (2N) Produces somatic (body) cells A process of cell division DNA is replicated in prophase Produces 4 different cells Produces haploid cells (1N) Produces gametes (sex cells)