1. Chromosomes in Metaphase

3. Chromosomal Mutations

4. Quiz Draw a Chromosome in Metaphase and label the main parts.
List Chromosomal Mutations.
What factors generate mutations? Ex.

5. CELL DIVISION

6. THE PURPOSE OF MITOSIS and MEIOSIS
EUKARYOTES: GROWTH AND REPAIR OF OLD/DAMAGED CELLS
PROKARYOTES: REPRODUCTION (TO MAKE IDENTICAL OFFSPRING)
MEIOSIS:
MOST EUKARYOTES: FOR SEXUAL REPRODUCTION: CREATING SEX CELLS
THESE SEX CELLS WILL BE GENETICALLY DIFFERENT. THIS INCREASES A SPECIES’ ADAPTABILITY=potential for evolution
Mitosis occurs in somatic cells: any cell in the body that’s not a sex cell
Meiosis occurs in reproductive cells like the ovary and testes.

7. CELL DIVISION: PROKARYOTES (creates new identical organism)
Circular DNA makes a copy of itself
Cell continues to grow until about twice its original size
Cell wall forms between to chromosomes

8. CELL Division: Eukaryotes
MITOSIS: somatic cells
For growth of organism
Repair of damaged cells
MEIOSIS: sex cells
For sexual reproduction (creation of sex cells)

9. THE CELL CYCLE
INTERPHASE: Time between cell divisions. It includes G1, S, and G2.
CELL DIVISION: Includes Mitosis (M phase) and Cytokinesis

10. CELL CYCLE G1:cell grows to mature size S: DNA is copied
G2: Cell prepares for cell division
*G0: Cells don’t copy their DNA & don’t prepare for division. Example: nerve cells stop dividing (nerve damage is permanent)

11. MITOSIS
Division of the nucleus into two identical nuclei (Mitosis is not cell division but first step in process)
Without mitosis, cell division would result in an uneven amount of chromosomes per cell---bad!!! (information lost)
4 steps: Prophase, Metaphase, Anaphase, and Telophase (PMAT)

12. MITOSIS STEPS SUMMARY Prophase: Copied DNA coils until visible
Nuclear envelope disappears
Spindle fibers form
Metaphase:
Chromosomes line up in the middle
Anaphase: Chromatids separate to opposite sides
Telophase: A new nuclear envelope forms around each new cell

13. Cytokinesis
Animal cells: Cell pinches inward creating a cleavage furrow until two cells are created
Plant cells: A cell plate forms in the middle and then the cell divides

14. Meiosis The creation of sex cells (gametes) like sperm and egg
Reduces the number of chromosomes by half
Has two cell division steps that result in 4 genetically different chromosomes!!!!!
(Here’s where evolution kicks in!)

15. How does meiosis create genetically diverse sex cells?
Independent assortment:
Chromosomes from mom or dad can go to whichever cell and don’t necessarily go together.
Crossover:
Homologous chromosomes trade off information, bits and pieces move