2. Cell Division Pre-existing cells growth and to replace damaged or old cells

3. DNA must be copied or replicated before cell division

4.  Tissue-  Organ- group of tissues that perform a  Organ system- multiple organs that work together groups of cells that work together to perform a specific function complex function

5. Chromosomes are found in every cell of our body. CHROMOSOMES In order to be alive, we need a full set of chromosomes = 46. ( 23 pairs of chromosomes ) Each chromosome pairs up with its partner that looks identical to it ( they both hold the same genes ) Chromosomes: rod-like structures in nucleus that contain hereditary information (DNA) & appear as long, thin threads called chromatin

6.  Asexual Reproduction  2 daughter cells produced from a parent cell

7.  Replication of an organism  Cytoplasm divides equally into two  Produces a new organism  Bacteria  Amoeba  Paramecium

8.  Mitotic division of the cytoplasm  Organism develops a “bud”  Cytoplasm does NOT divide equally  Yeast  Hydra

9.  Spores are produced by the organism /host  Spores released and grow into new organism  Bread mold

10.  Organism can replace damage cells OR  Part of an organism grows into a new organism  Lizard  Starfish  Planaria  Lobster claws

11. Spiny Brittlestar Regenerating arm

12.  Occurs in plants  Part of a root, stem or leaves  Grows into a new plant  Bulbs

13. “All cells arise from preexisting cells” (Virchow)

14. A karyotype is a way for scientists to check chromosomes Karyotypes are images of chromosomes to display their banding patterns.

15. NORMAL KARYOTYPE

16. Sex Chromosome ABNORMAL KARYOTYPE Down Syndrome

17. Sister chromatids Centromere

18. Asexual  1 parent  Offspring are identical to parent & to each other  No special organs/cells  Process that divides cells = mitosis  In one-celled organisms = new organism  In multi-cellular organisms = growth & repair Sexual  2 parents  Fusion of sperm & egg nuclei  Offspring have a combination of traits from both parents  Process that creates new cells = meiosis  Produces sperm & eggs

19.  Is the division of the nucleus  Only occurs in eukaryotes  Doesn’t occur in some cells such as brain cells  Occurs only in the body cells, known also as somatic cells  Results in 2 daughter cells which are identical to the parent cell AND each other

20.  Why is Mitosis important for unicellular organisms?  Form of reproduction  Every time an amoeba divides by mitosis a new identical amoeba is formed!

21.  Cell specialization!  Separate roles for each type of cell in the body of a multi-cellular organism  Skin cells, muscle cells, liver cells

22.  The Cell Cycle: a series of events that cells go through as they divide Mitosis clip..\bi omovie s\mitosi s part 1.mov..\bi omovie s\mitosi s part 1.mov Part 22

24.  A period of growth  Occurs right before mitosis  Cell increases in size  DNA is copied  Organelles needed for cell division are produced  Then, mitosis (cell division) occurs with 4 remaining phases:

25. Chromatin condenses to form Chromosomes Chromosomes make a copy of themselves Spindle fibers grow Nuclear membrane disappears Centrioles move to opposite ends of the cell

26. These are homologous pairs of chromosomes in the nucleus Cell Membrane Prophase

27.  Meta = middle  Chromatids line up in middle on “equator”  Spindle fibers attach to centromeres

28. centrioles Doubled chromosomes line up in the center of the cell. Cell Membrane Metaphase

29.  “AWAY”  Doubled Chromosomes are attached to spindle fibers Chromatids get ripped apart from each other Chromatids are pulled to opposite sides of the cell

30. Cell Membrane Anaphase

31.  The cell membrane pinches in  Each new cell is now in interphase  New nuclear membrane forms  Chromosomes unwind, pull up & become chromatin once again

32. Chromosomes on opposite sides of the cell form 2 new nuclei. Telophase New Nuclear membranes!! MitosisMitosis 2

33. Cytokinesis (the Last step!) Last Step!! We’ve got to divide the rest of the cell! A new cell membrane forms between the cells & 2 Daughter Cells!!!!! clip

34.  2 identical cells/ no variety  Mitosis Maintains Chromosome # http://www.cellsalive.com/mitosis.htm PROPHASE ANAPHASE INTERPHASE Animal Cell

36.  Animal Cell  The cell membrane is drawn inward  They have centrioles  Cytoplasm is pinched into 2 equal parts Plant Cell  Cell plate develops into a separating membrane

37.  Chromosome number stays the same from generation to generation  2 “daughter cells” produced, each one identical to “mother cells”