1. Warm-up What happens in mitosis? Today’s Objective:
I understand the difference between mitosis and meiosis
Homework: mitosis and meiosis graphic organizer

2. Mitosis/Meiosis

3. MITOSIS 2N 2N 2N
ALL CELLS AND DNA IDENTICAL

4. Mitosis Occurs in Somatic (body) cells
Used in growth & repair of body cells, Asexual reproduction

5. Starts with
Parent cell – (Diploid - 2N) – has both sets of chromosomes
Ends with
2 identical daughter cells (diploid)

6. Cells will turn into this
Daughter cells will turn into fully functional body cells (liver cells, muscle cells, etc.)

7. Chromosome Number
Stay the same (46 chromosomes in humans)

8. Genetic material
Stays the same (identical)

9. Problems
Uncontrolled growth or division causes cancer

10. 4 NEW GENETICALLY DIFFERENT CELLS
Meiosis 2N
Division I
Division II 1N 1N 1N 1N
4 NEW GENETICALLY DIFFERENT CELLS

11. Meiosis
Occurs in Gametes (sex cells)
Used in Sexual reproduction

12. Starts with
Diploid cell (2N)

13. Ends with 4 Haploid (1N) cells – 1 set of chromosomes
Called a Reduction division (2N to 1N)

14. Cells will turn into this
Males – 4 sperm
Females – 1 egg and 3 polar bodies

15. Chromosome Number Divides in half (46 to 23 chromosomes)
Sperm (23) and egg (23) combine to form a zygote (46) during fertilization
This ensures chromosome # is right

16. Genetic material
Genetic Variation caused by crossing over – chromatids overlap, break apart, and reattach to form new combinations of DNA

17. Problems
Zygotes with wrong chromosome # usually will not survive

18. Mitosis
Meiosis
Purpose
Growth,Repair
Sexual Reproduction
Chromosome #
2N to 2N
2N to 1N
# of cells produced 2 4
# of divisions 1
Genetic Material
Stays the same
Variation in gametes
Where it occurs
Somatic cells
Gametes

19. Meiosis Animation

20. DIPLOID
REDUCTION

21. HAPLOID
HAPLOID
DIVISION

22. Sperm and Egg Development
What types of chromosomes
Are in there?

24. Genetic Variation

25. http://highered. mcgraw-hill