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Chapter 11.4 Meiosis . IQ # 2 - Meiosis Review. What is a Tetrad? Is it a homologous chromosome? What is the difference between a homologous chromosome and a sister chromatid? What phase do homologous chromosome pairs separate? What phase do sister chromatids separate?
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IQ # 2 - Meiosis Review • What is a Tetrad? Is it a homologous chromosome? • What is the difference between a homologous chromosome and a sister chromatid? • What phase do homologous chromosome pairs separate? What phase do sister chromatids separate? • What is more similar to Mitosis, Meiosis I or Meiosis II?
Agenda • Work on Vocabulary (11.4) in class – 10 minutes • Lecture and Discussion – Finish 10.3 – Start 11.4 • Overhead Drawings? • Homework 11.4 Section Assessment
11.4 Meiosis Heredity ______________ – the passing of characteristics or traits from one generation to the next. • . Asexual Reproduction • . a single celled organism undergoes ______________ to create 2 identical offspring • . prokaryotes undergo ______________ to create 2 identical offspring binary fission mitosis
11.4 Meiosis • . Sexual Reproduction • . ______________ must occur between 2 specialized reproductive cells (gametes). • .______________ - the division of a cell to create gametes with __ the genetic information of a normal cell fertilization Meiosis 1/2
A. Purpose of Meiosis Haploid reduction variation • Purpose of Meiosis • __________ gametes – ____________ division • genetic ______________ • crossing over • independent assortment 2n 2n n 46 46 23 8 8 4 6 12 12
B. Phases of Meiosis Interphase Meiosis 1Meoisis II • Interphase – a. G phases (G1 & G2) - cell growth, protein synthesis organelle production b. S phase - DNA replication
B. Phases of Meiosis 2. Meiosis I – segregation of __________ Homologous pairs Prophase I Interphase I • PROPHASE I • homologous pairs form _________ • nucleus and nucleolus _________ • _______________ occurs • 2n, duplicated tetrads disappear crossing over
Prophase I Metaphase I Anaphase I Interphase I • METAPHASE I • spindle fibers attach • tetrads____________ • *Independent Assortment line up • ANAPHASE I • homologous pairs (alleles) _____________ (segregate) • *Principle of Segregation separate
Prophase I Metaphase I Anaphase I Interphase I Telophase I (with cytokinesis) • TELOPHASE I (with cytokinesis) • nuclear membrane reforms • 2 ______________ daughter cells • ______________ • 1n, duplicated haploid not identical
B. Phases of Meiosis sister chromatids 3. Meiosis II – separation of _________________ chromatids 4 haploid separate gametes
Agenda • Finish 11.4 Lecture • Overhead drawings of Meiosis stages • Review IQ answers • If you owe me checkpoint materials, see me after class • Tomorrow is a makeup-makeup day
C. Formation of Gametes 1. Female – ______________ a._____ haploid cells are produced • 1 viable cell (gamete) = ___________ • 3 ________________ due to unequal distribution of cytoplasm and organelles 2. Male – Spermatogenesis a. 4 viable cells (gametes) = ______________ oogenesis 4 egg polar bodies sperm http://wps.prenhall.com/esm_freeman_biosci_1/7/1957/501052.cw/index.html
Comparison of Mitosis and Meiosis *Handout
Mitosis Meiosis Number of daughter cells Type of cells produced Number of divisions Number of DNA replications Purpose of division Comparison of Meiosis and Mitosis 2 diploid cells 4 haploid cells Somatic Cells/ Body cells gametes 2 1 1 1 Growth, repair, asexual reproduction Sexual reproduction, genetic variation
Karyotype http://www.genomenewsnetwork.org/resources/whats_a_genome/Chp1_2_1.shtml
Crossing Over: exchange of genetic material between homologous pairs of chromosomes Go to Section:
Crossing Over Section 11-4
IQ # 2 - Meiosis Review • What is a Tetrad? Is it a homologous chromosome? • What is the difference between a homologous chromosome and a sister chromatid? • What phase do homologous chromosome pairs separate? What phase do sister chromatids separate? • What is more similar to Mitosis, Meiosis I or Meiosis II?
IQ # 1 10.1-10.2 • Why is it advantageous to have smaller cells as opposed to larger cells? • Explain “DNA Overload”? • Draw a chromosome and label its parts. • Define Mitosis. What is the difference between Mitosis and Cell Division?