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Reproduction. http://waynesword.palomar.edu/lmexer2a.htm. Remember from Chapter 1: CHARACTERISTICS OF LIVING THINGS ALL LIVING THINGS __________. REPRODUCE. ASEXUAL. SEXUAL.

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Reproduction

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  1. Reproduction http://waynesword.palomar.edu/lmexer2a.htm

  2. Remember from Chapter 1:CHARACTERISTICS OF LIVING THINGSALL LIVING THINGS __________ REPRODUCE ASEXUAL SEXUAL Planaria animation: http://www.t3.rim.or.jp/~hylas/planaria/title.htmFamily http://babyhearing.org/Parenet2Parent/index.asp

  3. ASEXUAL REPRODUCTION http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookmito.html BINARY FISSION Bacteria reproduce using __________________________________ Budding & regeneration are used by plants and animals to reproduce asexually (mitosis) 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

  4. BINARY FISSION & MITOSIS identical Produces cells that are __________ copies of parent cell

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

  6. 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

  7. SEXUAL REPRODUCTION Family image from: http://babyhearing.org/Parenet2Parent/index.asp Combines genetic material from 2 parents (sperm & egg) Offspring are genetically different from parents

  8. 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

  9. MEIOSIS is the way… to make cells with ½ the number of chromosomes for sexual reproduction http://waynesword.palomar.edu/lmexer2a.htm If egg and sperm had same number of chromosomes as other body cells . . . baby would have too many chromosomes!

  10. KARYOTYPE A __________ is a picture of an organism’s chromosomes

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

  12. WHAT MAKES MEIOSIS DIFFERENT ? • 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

  13. WHAT MAKES MEIOSIS DIFFERENT? CROSSING OVER 1. Exchange of DNA betweenhomologous pairs = _____________during PROPHASE I Allows shuffling of genetic material Places where crossing over happens = ____________________ CHIASMATA http://www.emc.maricopa.edu/faculty/farabee/BIOBK/Crossover.gif

  14. Image modified by Riedell CROSSING OVER • Allows for_________________ in different combinations • After crossing over, chromatid arms are________________ anymore rearranging of DNA NOT IDENTICAL http://sps.k12.ar.us/massengale/genetics%20tutorial.htm

  15. SEGREGATION(Anaphase I) • Orientation of the chromosome pairs is random with respect to the poles • Separation of homologous chromosomes ensures that each gamete receives a haploid set of chromosomes composed of both maternal and paternal chromosomes

  16. SEGREGATION & CROSSING OVERtogether make even more combinations See ananimation http://waynesword.palomar.edu/lmexer2a.htm

  17. INDEPENDENT ASSORTMENT http://fig.cox.miami.edu/~cmallery/150/mitosis/c13x9independent-assortment.jpg

  18. INDEPENDENT ASSORTMENTat 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!

  19. GENETIC RECOMBINATIONcomes from: • Crossing over • Segregation • Independent assortment • Random fertilization • fusion of two gametes, increase genetic variation in populations by providing new combinations of genetic information in the zygote, and restores diploid number of chromosomes

  20. Phases of Meiosis

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

  22. Figure 11-17 Meiosis II Section 11-4 Meiosis II 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.

  23. MITOSIS vs MEIOSISINTERPHASE 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

  24. 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 chromosomesNuclear membrane/ nucleolus disappear Centrioles/ spindle fibers appear Homologous pairs match up

  25. 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

  26. MITOSIS vs MEIOSIS ANAPHASE ANAPHASE I http://www.pbs.org/wgbh/nova/baby/divi_flash.html APART: Chromatids split APART: Chromatids stay togetherHomologous pairs split

  27. 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

  28. MITOSIS vs MEIOSIS CYTOKINESIS CYTOKINESIS I http://www.pbs.org/wgbh/nova/baby/divi_flash.html Cytoplasm splits into 2 cells SAME AS MITOSIS

  29. 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

  30. 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

  31. MITOSIS vs MEIOSIS METAPHASE METAPHASE II http://www.pbs.org/wgbh/nova/baby/divi_flash.html • Chromosomes line up in middle SAME AS MITOSIS

  32. MITOSIS vs MEIOSIS ANAPHASE ANAPHASE II http://www.pbs.org/wgbh/nova/baby/divi_flash.html Chromatids split and move apart SAME AS MITOSIS

  33. MITOSIS vs MEIOSIS TELOPHASE TELOPHASE II http://www.pbs.org/wgbh/nova/baby/divi_flash.html Two nuclei Nuclear membrane/nucleolus returns Centrioles/spindle fibersdisappear DNA spreads out as chromatin SAME AS MITOSIS

  34. MITOSIS vs MEIOSIS CYTOKINESIS CYTOKINESIS II http://www.pbs.org/wgbh/nova/baby/divi_flash.html Cytoplasm splits SAME AS MITOSIS http://www.pbs.org/wgbh/nova/baby/divi_flash.html

  35. 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 1ncells

  36. Nondisjunction – Failure of homologous chromosomes OR chromatids to separate at anaphase

  37. Mistakes in Meiosis Meiosis Lecture 4

  38. Nondisjunction Results in ANEUPLOIDY =one or more chromosomes have extra or missing copies AFTER FERTILIZATION:Cell with only 1 copy of a chromosome instead of 2 = MONOSOMY Cell with 3 copies of a chromosome instead of 2 = TRISOMY

  39. Errors in mitosis or meiosis can result in changes in phenotype • Changes in chromosome number often result in: • New phenotypes • Sterility caused by triploidy and increased vigor of other polyploids • human disorders with developmental limitations • Trisomy 21 (Down syndrome) • XO (Turner Syndrome)

  40. Karyotype can show: • Sex of baby • Missing or extra chromosomes • Major deletions or translocations • Can’t see individual gene changes http://content.answers.com/main/content/wp/en/thumb/f/f3/220px-Down_syndrome_translocation.png

  41. Down syndrome (Trisomy 21) Most common chromosomal abnormality (1 in 800 births) Similar facial featuresSlanted eyes / Protruding tongueMild to severe mental retardation 50% have heart defects that need surgery to repair http://www.hadsa.org/ Both older (35+ years) and younger (under 16 years) mothers are more at risk. http://www.healthofchildren.com/images/gech_0001_0002_0_img0096.jpg

  42. Some individuals with Down syndrome have the normal number of chromosomes but have all or part of a third chromosome 21 attached to another chromosome by translocation. http://content.answers.com/main/content/wp/en/thumb/f/f5/180px-Down_syndrome_translocation.png

  43. Turner syndrome (X0) http://medgen.genetics.utah.edu/photographs/diseases/high/611.gif 1 in 5000 births Females have only one X chromosome Small size Broad chest Slightly decreased intelligence 35% have heart abnormalities Hearing loss common Reproductive organs don’t develop at puberty

  44. http://www.akdeniz.edu.tr/tip/histoloji/embrders_dosyalar/slide0228_image1186.jpghttp://www.akdeniz.edu.tr/tip/histoloji/embrders_dosyalar/slide0228_image1186.jpg Klinefelter syndrome 1 in 2000 births live births Males have extra X chromosomes (Can be XXy, XXXy, or XXXXy) Taller than average Normal intelligencehave male sex organs, but are sterile.may be feminine characteristics, Often not discovered until puberty when don’t mature like peers Presence of BARR BODIES

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