2. 1/20/15 Starter: What is a chromosome? 1/20/15 133 134 Mitosis/Meiosis Application Notes Connection : WS Exit: 1.How many chromosomes do human cells have? 2. Do all humans have the same number of chromosomes in their cells? 3. But you were made from one cell from your mom and one cell from your dad, so how is it the same? Shouldn’t you have double the number of chromosomes? 4. Given this information, how many chromosomes do sex cells have? Mitosis/Meiosis Practice: Watch Video and write 5 things you learn

3. 1 Starter 2. Practice 3. Ws

4. Date Lecture/ Activity/ Lab Page 1/20 Mitosis/Meiosis 133-134 Table of Contents

6. Asexual ReproductionSexual Reproduction Uses only mitosis Produces clones—genetically identical offspring Fast and effective reproduction to spread organism No diversity Combination of two haploid sex cells Fertilization: combines genetic information from two separate cells with ½ of the original genetic information of parent organism Gametes are from separate parents. (female = egg, male = sperm) Zygote (new individual) has two sets of chromosomes, one from each parent Process changes diploid cells to haploid gametes—leading to an increase in diversity of offspring

7.  What is the advantage of an organism that reproduces sexually rather than asexually?  An organism that reproduces sexually will have more genetic diversity than one that reproduces asexually.

8.  Mitosis: -division of somatic (body) cells  Meiosis -division of gametes (sex cells)

9.  I nterphase  P rophase  M etaphase  A naphase  T elophase

10. Interesting things happen! 1. Cell preparing to divide 2. Genetic material doubles

11. Early: 1. Chromosome pair up! 2. Chromosomes thicken and shorten and become visible 3. Two chromatids joined by a centromere

12. Late: 1. Centrioles move to the opposite sides of the nucleus 2. Nucleolus disappears 3. Nuclear membrane disintegrate

14. 1. Chromosomes meet in the middle! 2. Chromosomes arrange at equator of cell Become attached to spindle fibres by centromeres 3. Homologous chromosomes do not associate

16. 1. Chromosomes get pulled apart 2. Spindle fibres contract pulling chromatids to the opposite poles of the cell

17.  Now there are two! 1. Chromosomes uncoil 2. Spindle fibres disintegrate 3. Centrioles replicate 4. Nucleur membrane forms 5. Cell divides

20.  Interphase  Prophase  Metaphase  Anaphase  Telophase

21.  Four daughter cells produced  Each daughter cell has half the chromosomes of the parent  Two sets of cell division involved  Similar to mitosis BUT no synthesis phase (no DNA replication)  Chromatids are NOT identical because of crossing over (recombination).

23. 1/20/15 Starter: What is a chromosome? 1/20/15 133 134 Mitosis/Meiosis Application Notes Connection : WS Exit: 1.How many chromosomes do human cells have? 2. Do all humans have the same number of chromosomes in their cells? 3. But you were made from one cell from your mom and one cell from your dad, so how is it the same? Shouldn’t you have double the number of chromosomes? 4. Given this information, how many chromosomes do sex cells have? Mitosis/Meiosis Practice: Watch Video and write 5 things you learn