1. Bell Ringer

2. Cell Division Review
Units 5 & 6

3. Prokaryotic Cell Division
Prokaryotic Cell Division = Binary Fission
After DNA replication occurs, the cytoplasm divides. There is NO nucleus, so mitosis does NOT happen.

4. This process is called Binary Fission
DNA Replication
Cytokinesis
This process is called Binary Fission

5. This is the Cell Cycle
M Phase

6. Eukaryotic Somatic (Body) Cell Division = Mitosis
Stages of Cell Cycle
Interphase
G1 = Growth
S = DNA replication
G2 = Prepare for Mitosis
M Phase
Mitosis = Division of Nucleus
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis = Division of Cytoplasm

7. REPRODUCTION OF BODY CELLS PRODUCES 2 IDENTICAL DIPLOID CELLS
MITOSIS
REPRODUCTION OF BODY CELLS
PRODUCES
2 IDENTICAL DIPLOID CELLS

8. Interphase
Cell Grows & Prepares for Division
DNA is Replicated

9. Prophase Nuclear Membrane & Nucleolus Disappear SPINDLE FORMS
Chromosomes become visible
Nuclear Membrane & Nucleolus Disappear
SPINDLE FORMS
EARLY
LATE

10. Metaphase Spindle Fibers attach to the Centromeres
Chromosomes Line up in the Middle/ Equator

11. Anaphase
Sister Chromatids are Pulled Apart (separated) to opposite poles of the cell

12. Telophase Nuclear Membrane & Nucleolus Reform
Chromosomes Unwind into Chromatin

13. Occurs during Telophase
Cytokinesis
Cytoplasm Divides
2 Identical daughter cells form with the SAME number of chromosomes as parent cell
Occurs during Telophase

14. Produces 2 Genetically Identical Diploid Body (Somatic) Cells
MITOSIS
END RESULT:
Produces 2 Genetically Identical Diploid Body (Somatic) Cells

15. Cytokinesis
ANIMAL CELL
PLANT CELL

16. MEIOSIS REPRODUCTION OF SEX CELLS PRODUCES
4 GENETICALLY DIFFERENT HAPLOID GAMETES

17. Interphase
Cell Grows & Prepares for Division
DNA is Replicated

18. Meiosis I
Prophase I
Metaphase I
Anaphase I
Telophase I

19. Meiosis II 2 Stages of Division Prophase II Metaphase II Anaphase II
HAPLOID 4
Prophase II
Metaphase II
Anaphase II
Telophase II

20. Synapsis/Tetrad = Homologous Chromosomes Pair Up & Cross Over
Crossing Over
 Synapsis/Tetrad = Homologous Chromosomes Pair Up & Cross Over
Crossing Over begins during Prophase I & ends during Anaphase I
Crossing Over is important because
It increases Genetic Diversity
It ensures that all cells produced during meiosis are Different
It Unlinks genes

22. Homologous Chromosomes Pair Up & Cross Over
Homologous Chromosomes Line Up In The Middle (double line)

23. Homologous Chromosomes Separate
Meiosis I
Homologous Chromosomes Separate

24. Spindle Reforms & Chromosomes Attach
Chromosomes Line Up
in the Middle
(single line)
Sister Chromatids Separate

25. Produces 4 Genetically Different Haploid Gametes (Sex Cells)
Meiosis II
Produces 4 Genetically Different Haploid Gametes (Sex Cells)

26. 1 ovum (egg) produced
4 sperm produced
Fertilization
Zygote

27. Karyotype: Male or Female?

28. Karyotype: Male or Female?

29. Human Gametes normally have 23 chromosomes.
Human Body Cells normally have 46 chromosomes (23 pairs).

30. What is this disorder called? Down’s Syndrome OR Trisomy 21
This is caused by Nondisjunction.
Nondisjunction can occur during Anaphase I OR Anaphase II of meiosis if the chromosomes do not SEPARATE correctly.

31. Stage of Meiosis = Anaphase I Stage of Meiosis = Anaphase II
Too Many Chromosomes

32. Homologous Chromosomes Line Up in the Middle/Equator
Crossing Over
Homologous Chromosomes Line Up in the Middle/Equator
Chromosomes Line Up in the Middle/Equator
Homologous Chromosomes Separate
Sister Chromatids Separate
Diploid
Haploid 4 2
Identical Body Cells
Genetically Different Gametes (sex cells)