MEIOSIS 11-4 Making gametes… 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? 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? 3. In order to produce a fertilized egg with the appropriate number of chromosomes (46), how many chromosomes should each sperm and egg have? 46 chromosomes 46 + 46 = 92; a developing embryo would not survive if it contained 92 chromosomes. Sperm and egg should each have 23 chromosomes.

Meiosis is used for reproduction Meiosis is used for reproduction. ALL LIVING THINGS __________ so all living things must go through the process of meiosis. REPRODUCE Planaria animation: http://www.t3.rim.or.jp/~hylas/planaria/title.htm Family http://babyhearing.org/Parenet2Parent/index.asp

ASEXUAL REPRODUCTION Bacteria reproduce using BINARY FISSION http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookmito.html Bacteria reproduce using __________________________________ Budding & regeneration are used by plants and animals to reproduce asexually (mitosis) BINARY FISSION http://fig.cox.miami.edu/~cmallery/150/mitosis/c7.13.2.hydra.jpg Planaria animation: http://www.t3.rim.or.jp/~hylas/planaria/title.htm

Binary fission and mitosis reproduce cells that are __________ copies of the parent cell. identical

ADVANTAGES OF ASEXUAL REPRODUCTION Can make offspring faster Don’t need a partner http://www.mrgrow.com/images/cutting.jpg

DISVANTAGES OF ASEXUAL REPRODUCTION Organisms are ALL ALIKE Species CAN’T change and adapt One disease can wipe out whole population http://www.mrgrow.com/images/cutting.jpg

SEXUAL REPRODUCTION DIFFERENT Combines genetic material Family image from: http://babyhearing.org/Parenet2Parent/index.asp Combines genetic material from 2 parents (sperm & egg) so offspring are genetically __________ from parents DIFFERENT

ADVANTAGES OF SEXUAL REPRODUCTION Allows for variation in populations Individuals can be different Provides foundation for EVOLUTION Allow species adapt to changes in their environment http://naturalsciences.sdsu.edu/classes/lab8/spindex.html

+ WHY MEIOSIS? EGG SPERM  Humans have 46 chromosomes http://www.angelbabygifts.com/ Image by Riedell WHY MEIOSIS? Image by Riedell EGG + SPERM  Humans have 46 chromosomes in their body cells. 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… to make cells with half the number of chromosomes for sexual reproduction http://waynesword.palomar.edu/lmexer2a.htm Meiosis Overview

DIPLOID & HAPLOID Most cells have 2 copies of each chromosome = _________ or _____ (one from mom; one from dad) All BODY (___________) cells are diploid DIPLOID 2n 2 copies of each chromosome is called: HOMOLOGOUS CHROMOSOMES = SOMATIC

DIPLOID & HAPLOID Some cells have only one copy of each chromosome = _____________ All sperm and egg cells are haploid HAPLOID 1n

MITOSIS Makes ___ cells genetically _________ to parent cell & to each other Makes ___ cells Makes __________ Used by organisms to: increase size of organism, repair injuries, replace worn out cells 2 identical 2n SOMATIC (body) cells http://waynesword.palomar.edu/lmexer2a.htm

MEIOSIS 4 1n Gametes (sperm & eggs) sexual reproduction Makes ____ cells genetically different from parent cell & from each other Makes _____ cells Makes ______________ Used for ____________ 1n Gametes (sperm & eggs) sexual reproduction http://waynesword.palomar.edu/lmexer2a.htm

WHAT MAKES MEIOSIS DIFFERENT from MITOSIS ? SYNAPSIS & CROSSING OVER (PROPHASE I) SEGREGATION & INDEPENDENT ASSORTMENT (ANAPHASE I) 3. Skips INTERPHASE II (NO S phase) CELL DIVIDES TWICE, BUT… ONLY COPIES DNA ONCE

WHAT MAKES MEIOSIS DIFFERENT ? Homologous chromosomes pair up during ________________ = ______________ PROPHASE I SYNAPSIS This group of FOUR 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 homologous pairs = _____________ during PROPHASE I CROSSING OVER Allows shuffling of genetic material http://www.emc.maricopa.edu/faculty/farabee/BIOBK/Crossover.gif

HOMOLOGOUS CHROMOSOMES SAME SIZE SAME SHAPE CARRY GENES for the SAME TRAITS BUT ______________! (Don’t have to have the SAME CHOICES) Image modified by Riedell NOT IDENTICAL http://sps.k12.ar.us/massengale/genetics%20tutorial.htm

Allows for_________________ in different combinations Image modified by Riedell CROSSING OVER rearranging of DNA Allows for_________________ in different combinations After crossing over, chromatid arms are________________ anymore NOT IDENTICAL 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

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 =______________________________ So daughter cells are ______________ from parents and from each other GENETIC RECOMBINATION different

WHAT MAKES MEIOSIS DIFFERENT ? 3. Skip INTERPHASE II (No S phase) CELL DIVIDES TWICE, BUT … ONLY COPIES ITS DNA ONCE MITOSIS: G1 S G2 P M A T C        MEIOSIS: ( I ) G1 A T C S G2 P M        P M A T C ( II )    

Figure 11-15 Meiosis Section 11-4 Meiosis I

Figure 11-15 Meiosis Section 11-4 Meiosis I Meiosis I

Figure 11-15 Meiosis Section 11-4 Meiosis I Meiosis I

Figure 11-15 Meiosis Section 11-4 Meiosis I

Figure 11-15 Meiosis Section 11-4 Meiosis I

Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.

Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.

Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.

Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.

Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. 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: APART: Chromatids split 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/ nucleolus return DNA spreads out as chromatin Spindle/centrioles disappear SAME AS MITOSIS

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 Nuclear membrane/ nucleolus visible DNA is copied during S phase SKIP INTERPHASE II 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 SAME AS MITOSIS Cytoplasm splits http://www.pbs.org/wgbh/nova/baby/divi_flash.html

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

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 predict how traits are transmitted from parents to offspring PROFICIENT level: describe the relationship between structure and function compare and contrast the cell cycles in somatic and germ cells; explain how traits are transmitted from parents to offspring; BASIC level recognize that different structures perform different functions describe the life cycle of somatic cells; 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.