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Bell Ringer. Cell Division Review Units 5 & 6 Prokaryotic Cell Division Prokaryotic Cell Division = Binary Fission After DNA replication occurs, the.

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Presentation on theme: "Bell Ringer. Cell Division Review Units 5 & 6 Prokaryotic Cell Division Prokaryotic Cell Division = Binary Fission After DNA replication occurs, the."— Presentation transcript:

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

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 MITOSIS REPRODUCTION OF BODY CELLS PRODUCES 2 IDENTICAL DIPLOID CELLS

8 Interphase Cell Grows & Prepares for Division DNA is Replicated

9 Prophase Chromosomes become visible Nuclear Membrane & Nucleolus Disappear SPINDLE FORMS EARLYLATE

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

14 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 IMetaphase I Anaphase ITelophase I

19 Meiosis II Prophase IIMetaphase II Anaphase IITelophase II 2 Stages of Division HAPLOID4

20 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

21

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

23 Meiosis I Homologous Chromosomes Separate

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

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

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

27 Karyotype: Male or Female?

28

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


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