1. Mitosis and the Cell Cycle
Big Idea:
Mitosis is the process in which the nucleus divides to form two new nuclei and two cells with identical DNA.
Mrs. Camp
7th Grade Life Science 1

2. How do little elephants grow up
to be BIG elephants?

3. Why do animals shed their skin?

4. Mitosis begins after fertilization
1 cell becomes 2 cells, becomes 4 cells…becomes TRILLIONS

5. Why do cells make more cells?
Three reasons why cells reproduce by asexual reproduction: Growth Repair Replacement

6. Important Terms Somatic Cells – body cells Produced through mitosis
Has 46 chromosomes (23 pairs)
Homolog – each member of a chromosome pair
Diploid (2n) – total of 46 chromosomes in people – zygote & somatic cells
Haploid (n) – total of 23 chromosomes in people, gametes (sperm & egg)

7. Animated Mitosis Cycle
Interphase
Prophase
Metaphase
Anaphase
Telophase & Cytokinesis

8. Interphase occurs before mitosis begins
Chromosomes are copied (# doubles)
Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase
CELL MEMBRANE
Nucleus
Cytoplasm

9. Interphase Plant Cell Animal Cell
Photographs from:

10. Stages of Interphase
Growth Stage 1 (G1) – metabolic activity of the cell
Synthesis Stage (S) – metabolic activity of the cell, replication of DNA
Growth Stage 2 (G2) – metabolic activity of the cell, prepare for division

11. Prophase 1st step in Mitosis
Mitosis begins (cell begins to divide).
Centrioles (or poles) appear and begin to move to opposite ends of the cell.
Nuclear Envelope disappears.
Spindle fibers form between the poles.
Centrioles
Sister chromatids
Spindle fibers

12. Prophase Plant Cell Animal Cell Spindle fibers
Photographs from:

13. Metaphase 2nd step in Mitosis
Chromatids (or pairs of chromosomes) attach to the spindle fibers at the centromere.
Chromosomes move to the equator of the cell.
Centrioles
Spindle fibers

14. Metaphase Plant Cell Animal Cell
Photographs from:

15. Anaphase 3rd step in Mitosis
Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell.
Centromere is broken in half.
Centrioles
Spindle fibers

16. Anaphase Plant Cell Animal Cell
Photographs from:

17. Telophase 4th step in Mitosis
Two new identical nuclei form (nuclear envelopes reform).
Chromosomes uncoil and appear as chromatin (threads rather than rods).
Mitosis ends.
Nuclei
Nuclei
Chromatin

18. Telophase Plant Cell Animal Cell
Photographs from:

19. Cytokinesis occurs after Mitosis
Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

20. Animal Mitosis -- Review
Interphase                                                             
Prophase                                                             
Metaphase                                                             
Anaphase                                                             
Telophase                                                             

21. Plant Mitosis -- Review
Interphase                                                             
Prophase                                                             
Metaphase                                                             
Anaphase                                                             
Telophase                                                             

22. IPMATC REMEMBER! Interphase Prophase Metaphase Anaphase Telophase
Cytokinesis
IPMATC
A mnemonic to help remember the stages of mitosis.
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23. Cell Cycle

24. - Cell Division
The Cell Cycle 24

25. Mitosis Animation