MEIOSIS 11-4 http://waynesword.palomar.edu/lmexer2a.htm Making gametes… Interest Grabber 1. How many chromosomes would a sperm or an egg contain if either one resulted from the process of mitosis? 46 chromosomes 2. If a sperm containing 46 chromosomes fused with an egg containing 46 chromosomes, how many chromosomes would the resulting fertilized egg contain? Do you think this would create any problems in the developing embryo? 46 + 46 = 92; a developing embryo would not survive if it contained 92 chromosomes. 3. In order to produce a fertilized egg with the appropriate number of chromosomes (46), how many chromosomes should each sperm and egg have? Sperm and egg should each have 23 chromosomes. Remember from Chapter 1: CHARACTERISTICS OF LIVING THINGS REPRODUCE ALL LIVING THINGS __________ Planaria animation: http://www.t3.rim.or.jp/~hylas/planaria/title.htm Family http://babyhearing.org/Parenet2Parent/index.asp ASEXUAL REPRODUCTION Bacteria reproduce using http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookmito.html BINARY FISSION __________________________________ http://fig.cox.miami.edu/~cmallery/150/mitosis/c7.13.2.hydra.jpg Budding & regeneration are used by plants and animals to reproduce asexually (mitosis) Planaria animation: http://www.t3.rim.or.jp/~hylas/planaria/title.htm BINARY FISSION & MITOSIS identical Produces cells that are __________ copies of parent cell ADVANTAGES OF ASEXUAL REPRODUCTION Can make offspring faster Don’t need a partner http://www.mrgrow.com/images/cutting.jpg DISVANTAGES OF ASEXUAL REPRODUCTION ALL ALIKE Species CAN’T change and adapt One disease can wipe out whole population http://www.mrgrow.com/images/cutting.jpg SEXUAL REPRODUCTION Family image from: http://babyhearing.org/Parenet2Parent/index.asp Combines genetic material from 2 parents (sperm & egg) so offspring are DIFFERENT genetically __________ from parents ADVANTAGES OF SEXUAL REPRODUCTION Allows for variation in population Individuals can be different Provides foundation for EVOLUTION Allow species adapt to changes in their environment http://naturalsciences.sdsu.edu/classes/lab8/spindex.html Image by Riedell EGG Image by Riedell + http://www.angelbabygifts.com/ SPERM If egg and sperm had same number of chromosomes as other body cells . . . baby would have too many chromosomes! http://www.acmecompany.com/stock_thumbnails/13217.forty-six_chromosomes.jpg MEIOSIS is the way… http://waynesword.palomar.edu/lmexer2a.htm to make cells with ½ the number of chromosomes for sexual reproduction Video 1 Meiosis Overview Click the image to play the video segment 11A. DIPLOID & HAPLOID Most cells have 2 copies of each chromosome DIPLOID 2n = ______________ (one from mom; one from dad) HOMOLOGOUS CHROMOSOMES All BODY (___________) = SOMATIC cells are diploid DIPLOID & HAPLOID Some cells have only one copy of each HAPLOID 1n chromosome = _____________ All sperm and egg cells are haploid MITOSIS • Makes ___ 2 cells genetically identical _________ to parent cell & to each other 2n • Makes ___ cells • Makes __________ SOMATIC (body) • Used by organisms to: increase size of organism, repair injuries, replace worn out cells http://waynesword.palomar.edu/lmexer2a.htm MEIOSIS 4 cells • Makes ____ genetically different from parent cell & from each other 1n cells • Makes _____ • Makes ______________ Gametes (sperm & eggs) • Used for ____________ sexual reproduction http://waynesword.palomar.edu/lmexer2a.htm WHAT MAKES MEIOSIS DIFFERENT ? 1. SYNAPSIS & CROSSING OVER (PROPHASE I) 2. SEGREGATION & INDEPENDENT ASSORTMENT (ANAPHASE I) 3. Skip INTERPHASE II (NO S) CELL DIVIDES TWICE, BUT… ONLY COPIES DNA ONCE WHAT MAKES MEIOSIS DIFFERENT ? 1. Homologous chromosomes pair up during ________________ PROPHASE I SYNAPSIS = ______________ This group of FOUR (4) chromatids is called a TETRAD _________________ Images modified from: http://www.emc.maricopa.edu/faculty/farabee/BIOBK/Crossover.gif WHAT MAKES MEIOSIS DIFFERENT? 1. Exchange of DNA between OVER homologous pairs = CROSSING _____________ during PROPHASE I Allows shuffling of genetic material http://www.emc.maricopa.edu/faculty/farabee/BIOBK/Crossover.gif Video 5 Crossing Over SEE CROSSING OVER ANIMATION Click the image to play the video segment. 11E HOMOLOGOUS CHROMOSOMES Image modified by Riedell • SAME SIZE • SAME SHAPE • CARRY GENES for the SAME TRAITS IDENTICAL • BUT NOT ______________! (Don’t have to have the SAME CHOICES) http://sps.k12.ar.us/massengale/genetics%20tutorial.htm Image modified by Riedell CROSSING OVER rearranging of DNA • Allows for_________________ in different combinations • After crossing over, chromatid arms NOT IDENTICAL anymore are________________ http://sps.k12.ar.us/massengale/genetics%20tutorial.htm WHAT MAKES MEIOSIS DIFFERENT ? 2.Separation during ANAPHASE I SEGREGATION & INDEPENDENT ASSORTMENT Separates gene choices and allows shuffling of genetic material Video 4 Segregation of Chromosomes Click the image to play the video segment 11D. SEGREGATION (Anaphase I) SEGREGATION & CROSSING OVER together make even more combinations See an animation http://waynesword.palomar.edu/lmexer2a.htm INDEPENDENT ASSORTMENT http://fig.cox.miami.edu/~cmallery/150/mitosis/c13x9independent-assortment.jpg INDEPENDENT ASSORTMENT at ANAPHASE I Lots of different combinations are possible! This is why you don’t look exactly like your brothers and sisters even though you share the same parents! http://www.tokyo-med.ac.jp/genet/anm/mimov.gi WHAT MAKES MEIOSIS DIFFERENT ? Crossing over Segregation Independent assortment are ALL ways MEIOSIS results in =______________________________ GENETIC RECOMBINATION different So daughter cells are ______________ from parents and from each other WHAT MAKES MEIOSIS DIFFERENT ? 3. Skip INTERPHASE II (No S) CELL DIVIDES TWICE, BUT … ONLY COPIES ITS DNA ONCE MITOSIS: 1 G S G2 P MEIOSIS: G1 S M G2 P M PM A T C A T C (I) A T C ( II ) Video 2 Animal Cell Meiosis, Part 1 & Part 2 Click the image to play the video segment 11B. & C Video 2 Figure 11-15 Meiosis Section 11-4 Meiosis I Go to Section: Figure 11-15 Meiosis Section 11-4 Meiosis I Go to Section: Figure 11-15 Meiosis Section 11-4 Meiosis I Go to Section: Figure 11-15 Meiosis Section 11-4 Meiosis I Go to Section: Figure 11-15 Meiosis Section 11-4 Meiosis I Go to Section: Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Meiosis I results in two The chromosomes line up in a The sister chromatids haploid (N) daughter cells, similar way to the metaphase separate and move toward each with half the number of stage of mitosis. opposite ends of the cell. chromosomes as the original. Go to Section: Telophase II Meiosis II results in four haploid (N) daughter cells. Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Meiosis I results in two The chromosomes line up in a The sister chromatids haploid (N) daughter cells, similar way to the metaphase separate and move toward each with half the number of stage of mitosis. opposite ends of the cell. chromosomes as the original. Go to Section: Telophase II Meiosis II results in four haploid (N) daughter cells. Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Meiosis I results in two The chromosomes line up in a The sister chromatids haploid (N) daughter cells, similar way to the metaphase separate and move toward each with half the number of stage of mitosis. opposite ends of the cell. chromosomes as the original. Go to Section: Telophase II Meiosis II results in four haploid (N) daughter cells. Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Meiosis I results in two The chromosomes line up in a The sister chromatids haploid (N) daughter cells, similar way to the metaphase separate and move toward each with half the number of stage of mitosis. opposite ends of the cell. chromosomes as the original. Go to Section: Telophase II Meiosis II results in four haploid (N) daughter cells. Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Meiosis I results in two The chromosomes line up in a The sister chromatids haploid (N) daughter cells, similar way to the metaphase separate and move toward each with half the number of stage of mitosis. opposite ends of the cell. chromosomes as the original. Go to Section: Telophase II Meiosis II results in four haploid (N) daughter cells. MITOSIS vs MEIOSIS INTERPHASE INTERPHASE I http://www.pbs.org/wgbh/nova/baby/divi_flash.html • DNA is spread out as chromatin • Nuclear membrane/ nucleolus visible • DNA is copied during S phase • Makes stuff new cell needs in G2 SAME AS MITOSIS MITOSIS vs MEIOSIS PROPHASE PROPHASE I http://www.pbs.org/wgbh/nova/baby/divi_flash.html DNA scrunches into chromosomes Nuclear membrane/ nucleolus disappear Centrioles/ spindle fibers appear DNA scrunches into chromosomes Nuclear membrane/ nucleolus disappear Centrioles/spindle fibers appear Homologous pairs match up MITOSIS vs MEIOSIS METAPHASE METAPHASE I http://www.pbs.org/wgbh/nova/baby/divi_flash.html • Chromosomes line up in middle Chromosomes line up in middle with homologous partner MITOSIS vs MEIOSIS ANAPHASE ANAPHASE I http://www.pbs.org/wgbh/nova/baby/divi_flash.html APART: Chromatids split APART: Chromatids stay together Homologous pairs split MITOSIS vs MEIOSIS TELOPHASE TELOPHASE I http://www.pbs.org/wgbh/nova/baby/divi_flash.html See TWO nuclei Nuclear membrane/ SAME AS MITOSIS nucleolus return DNA spreads out as chromatin Spindle/centrioles disappear MITOSIS vs MEIOSIS CYTOKINESIS CYTOKINESIS I http://www.pbs.org/wgbh/nova/baby/divi_flash.html Cytoplasm splits into 2 cells SAME AS MITOSIS MITOSIS vs MEIOSIS INTERPHASE II http://www.pbs.org/wgbh/nova/baby/divi_flash.html • DNA is spread out as chromatin SKIP • Nuclear membrane/ INTERPHASE II nucleolus visible • DNA is copied during S phase DNA NOT COPIED MITOSIS vs MEIOSIS PROPHASE PROPHASE II http://www.pbs.org/wgbh/nova/baby/divi_flash.html • DNA scrunches into chromosomes • Nuclear membrane/ nucleolus disappear • Centrioles/ spindle fibers appear SAME AS MITOSIS MITOSIS vs MEIOSIS METAPHASE METAPHASE II http://www.pbs.org/wgbh/nova/baby/divi_flash.html • Chromosomes line up in middle SAME AS MITOSIS MITOSIS vs MEIOSIS ANAPHASE ANAPHASE II http://www.pbs.org/wgbh/nova/baby/divi_flash.html Chromatids split and move apart SAME AS MITOSIS MITOSIS vs MEIOSIS TELOPHASE TELOPHASE II http://www.pbs.org/wgbh/nova/baby/divi_flash.html Two nuclei Nuclear membrane/ nucleolus returns Centrioles/spindle fibers disappear DNA spreads out as chromatin SAME AS MITOSIS MITOSIS vs MEIOSIS CYTOKINESIS CYTOKINESIS II http://www.pbs.org/wgbh/nova/baby/divi_flash.html Cytoplasm splits http://www.pbs.org/wgbh/nova/baby/divi_flash.html SAME AS MITOSIS Ways Meiosis is different? • Homologous pairs match up & trade DNA (SYNAPSIS & CROSSING OVER) in PROPHASE I •SEGREGATION & INDEPENDENT ASSORTMENT in Anaphase I create genetic recombination • Skipping INTERPHASE II(Dividing TWICE but copying DNA once) produces 1n cells MAKING SPERM & EGGS SPERMATOGENESIS ___________________= MAKING MATURE SPERM Mature & grow flagella Sperm provides DNA All the starting nutrients, organelles, molecule building blocks, etc. have to come from the egg. OOGENESIS __________________ = MAKING a MATURE EGG Produces: 1 “good” egg 3 POLAR BODIES CYTOPLASM DIVIDES UNEVENLY WHY MAKE ONLY ONE “GOOD” EGG? Sperm donates mostly DNA Most of the cell parts and nutrients needed for baby come from EGG! http://bestweekever.blogs.com/photos/uncategorized/imagemain_sperm_egg1_1.gif POLAR BODIES DEGENERATE (DIE) “Self digest” Using LYSOSOMES ________________ = __________________ APOPTOSIS “cell suicide” for good of organism SOUTH DAKOTA CORE SCIENCE STANDARDS LIFE SCIENCE: Indicator 1: Understand the fundamental structures, functions, classifications, and mechanisms found in living things 9-12.L.1.1. Students are able to relate cellular functions and processes to specialized structures within cells. Cell life cycles Examples: somatic cells (mitosis), germ cells (meiosis) Storage and transfer of genetic information SOUTH DAKOTA CORE SCIENCE STANDARDS LIFE SCIENCE: Indicator 2: Analyze various patterns and products of natural and induced biological change. 9-12.L.2.2. Students are able to describe how genetic recombination, mutations, and natural selection lead to adaptations, evolution, extinction, or the emergence of new species. Core High School Life Science Performance Descriptors High school students performing at the ADVANCED level: predict the function of a given structure; predict the outcome of changes in the cell cycle; INTRODUCTION TO BE ABLE TO DO LATER High school students performing at the PROFICIENT level: describe the relationship between structure and function compare and contrast the cell cycles in somatic and germ cells; INTRODUCTION TO BE ABLE TO DO LATER predict how traits are transmitted from parents to offspring explain how traits are transmitted from parents to offspring; High school students performing at the BASIC level recognize that different structures perform different functions describe the life cycle of somatic cells; INTRODUCTION TO BE ABLE TO DO LATER identify that genetic traits can be transmitted from parents to offspring; SOUTH DAKOTA ADVANCED SCIENCE STANDARDS LIFE SCIENCE: Indicator 2: Analyze various patterns and products of natural and induced biological change. 9-12.L.2.1A. Students are able to predict the results of complex inheritance patterns involving multiple alleles and genes. (SYNTHESIS) Examples: human skin color, polygenic inheritance relate crossing over to genetic variation.