MEIOSIS http://waynesword.palomar.edu/lmexer2a.htm Making gametes
Remember from Chapter 1: CHARACTERISTICS OF LIVING THINGS ALL LIVING THINGS 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 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 Produces cells that are copies of 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 ALL ALIKE Species CAN T change and adapt http://www.mrgrow.com/images/cutting.jpg One disease can wipe out whole population
SEXUAL REPRODUCTION 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 population Individuals can be different Provides foundation for EVOLUTION Allow species to adapt to changes in their environment http://naturalsciences.sdsu.edu/classes/lab8/spindex.html
Image by Riedell Image by Riedell http://www.angelbabygifts.com/ EGG + 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
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. Called gametes or sex cells.
MITOSIS Makes cells genetically 2 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 Makes cells genetically different from parent cell & from each other 1n Makes cells Makes Gametes (sperm & eggs) sexual Used for 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 PROPHASE I SYNAPSIS during = This group of FOUR (4) chromatids is called a TETRAD Images modified from: http://www.emc.maricopa.edu/faculty/farabee/biobk/crossover.gif
HOMOLOGOUS CHROMOSOMES Image modified by Riedell SAME SIZE SAME SHAPE CARRY GENES for the SAME TRAITS BUT NOT! IDENTICAL (Don t have to have the SAME CHOICES) http://sps.k12.ar.us/massengale/genetics%20tutorial.htm
WHAT MAKES MEIOSIS DIFFERENT? 2. Exchange of DNA between homologous pairs = CROSSING OVER during PROPHASE I Allows shuffling of genetic material http://www.emc.maricopa.edu/faculty/farabee/biobk/crossover.gif
Image modified by Riedell CROSSING OVER Allows for rearranging of DNA in different combinations After crossing over, chromatid arms are NOT IDENTICAL anymore http://sps.k12.ar.us/massengale/genetics%20tutorial.htm
WHAT MAKES MEIOSIS DIFFERENT? SEGREGATION & INDEPENDENT ASSORTMENT Separation of chromosomes during ANAPHASE I Separates gene choices and allows shuffling of genetic material
SEGREGATION (Anaphase I)
SEGREGATION & CROSSING OVER together make even more combinations 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? 3. Skip INTERPHASE II (No S) CELL DIVIDES TWICE, BUT G 1 S G 2 ONLY COPIES ITS DNA ONCE MITOSIS: P M A T C MEIOSIS: G 1 S G 2 P M A T C P M A T C ( I ) ( II )
WHAT MAKES MEIOSIS DIFFERENT? 1. Crossing over 2. Segregation 3. Independent assortment are ALL ways MEIOSIS results in = GENETIC RECOMBINATION So daughter cells are different from parents and from each other
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 Telophase II Meiosis I results in two The chromosomes line up in a haploid (N) daughter cells, similar way to the metaphase each with half the number of stage of mitosis. chromosomes as the original. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells. Go to Section:
Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two The chromosomes line up in a haploid (N) daughter cells, similar way to the metaphase each with half the number of stage of mitosis. chromosomes as the original. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells. Go to Section:
Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two The chromosomes line up in a haploid (N) daughter cells, similar way to the metaphase each with half the number of stage of mitosis. chromosomes as the original. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells. Go to Section:
Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two The chromosomes line up in a haploid (N) daughter cells, similar way to the metaphase each with half the number of stage of mitosis. chromosomes as the original. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells. Go to Section:
Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two The chromosomes line up in a haploid (N) daughter cells, similar way to the metaphase each with half the number of stage of mitosis. chromosomes as the original. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells. Go to Section:
MITOSIS vs MEIOSIS INTERPHASE http://www.pbs.org/wgbh/nova/baby/divi_flash.html INTERPHASE I DNA is spread out as chromatin Nuclear membrane/ nucleolus visible DNA is copied during S phase SAME AS MITOSIS
MITOSIS vs MEIOSIS PROPHASE http://www.pbs.org/wgbh/nova/baby/divi_flash.html PROPHASE I DNA scrunches into DNA scrunches into replicated chromosomes replicated chromosomes Nuclear membrane/ Nuclear membrane/ nucleolus disappear nucleolus disappear Centrioles/spindle fibers Centrioles/ spindle fibers appear appear Homologous pairs match up
MITOSIS vs MEIOSIS METAPHASE http://www.pbs.org/wgbh/nova/baby/divi_flash.html METAPHASE I Replicated chromosomes line up in middle Replicated 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 http://www.pbs.org/wgbh/nova/baby/divi_flash.html TELOPHASE I See TWO nuclei Nuclear membrane/ nucleolus return DNA spreads out as chromatin Spindle/centrioles disappear SAME AS MITOSIS
MITOSIS vs MEIOSIS CYTOKINESIS http://www.pbs.org/wgbh/nova/baby/divi_flash.html CYTOKINESIS I Cytoplasm splits into 2 cells SAME AS MITOSIS
MITOSIS vs MEIOSIS PROPHASE http://www.pbs.org/wgbh/nova/baby/divi_flash.html PROPHASE II DNA scrunches into replicated chromosomes Nuclear membrane/ nucleolus disappear Centrioles/ spindle fibers appear Two cells in meiosis II; no Homologous pairs
MITOSIS vs MEIOSIS METAPHASE METAPHASE II http://www.pbs.org/wgbh/nova/baby/divi_flash.html Replicated 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 2 daughter cells Cytoplasm splits 4 cells http://www.pbs.org/wgbh/nova/baby/divi_flash.html
MAKING SPERM & EGGS
SPERMATOGENESIS = MAKING MATURE SPERM Mature & grow flagella
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
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
POLAR BODIES DEGENERATE (DIE) Self digest Using LYSOSOMES = APOPTOSIS cell suicide for good of organism