1. Mitosis - Cell division

2. Living organisms have life cycles.
Life cycles begin with organism’s formation, followed by growth and development and end in death.

3. Individual cells have life cycles.
Some cells constantly complete the cycle, others take hours or longer.
Cell cycle is broken down into sections

4. Interphase The longest part of a cell’s life cycle
Several major things occur during Interphase;
The cell grows, develops.
Organelles are duplicated.
The DNA is copied (chromosomes duplicated)
The cell prepares for cell division.
Interphase is NOT part of mitosis.

5. Interphase

6. In Interphase, chromatids are duplicated.
When the nucleus is ready to divide, each duplicated chromosome coils into two thickened strands called chromatids.

7. Mitosis
Mitosis: process in which the nucleus divides to form two identical nuclei.
Steps of Mitosis: Prophase, Metaphase, Anaphase, and Telophase. (PMAT)

8. Prophase (Prepare) First step of mitosis
Chromatids are fully visible under a microscope
Nucleolus and nuclear membrane disintegrate
Two organelles called centrioles move to opposite ends in the cell.
Between the centrioles, (only in animal cells) thin threadlike structures called spindle fibers begin to stretch across the cell.

9. Metaphase (Middle)
The chromosomes line up across the midline of the cell.
The centromere of each chromosome becomes attached to the spindle fibers.

10. Anaphase (Apart)
The centromere, in the center of each pair of chromatids, splits in half.
The spindle fibers shorten, pulling the pair of chromatids apart.
Each pair of chromatids separate, and move to opposite ends of the cell.

11. Telophase (Two nuclei form)
Spindle fibers disappear.
Nuclear membrane reappears.
Chromosomes begin to uncoil and a new nucleolus forms.

12. Cytokinesis Division of the cytoplasm
In animal cells – the cell membrane pinches in the middle.
In plant cells – a cell plate forms followed by the formation of new cell walls .
Then cells enter into Interphase to repeat the cell cycle again.

13. Cytokinesis
Animal Cell
Why doesn’t a plant cell pinch in at the sides like an animal cell?
Plant Cell

14. Onion Root Tip Cells

15. Results of Mitosis Mitosis is the division of a nucleus.
The process produces two new nuclei that are identical to each other and to the original nucleus (clones).
The new cells have a full set of chromosomes (Diploid)

16. Why does mitosis happen?
Mitosis allows for:
Growth
Replacement of worn out or damaged cells
Reproduction - In some organisms, it is used to produce new organisms
GRR!!!!

17. Asexual Reproduction A new organism is produced from one organism.
The new organism has exactly the same hereditary material as the parent organism.

18. Asexual Reproduction in Plants

19. Asexual Reproduction in Animals
Budding and Regeneration

21. Prokaryotic organisms cannot undergo mitosis (they have no nucleus) They reproduce asexually using fission

23. What are the stages? Interphase Prophase Metaphase Anaphase Telophase
Cytokinesis

24. Identify each stage of the cell cycle (no cytokinesis stage)

25. Answers Metaphase 11. Metaphase Prophase 12. Telophase Telophase
Interphase
Anaphase
11. Metaphase
12. Telophase
13. Interphase
14. Prophase
15. Interphase
16. Interphase
17. Metaphase
18. Interphase
Which stage is the longest: Interphase

26. Summary To make more cells, a single cell must undergo __________
Mitosis will result in ____ cells being formed.
Each new cell has a complete full set of _________________ containing the DNA. (diploid)
Mitosis happens for three reasons:
a.____________ b. _______________
c. _________________
Mitosis
two
chromosomes
Growth
Replacement
Reproduction (assexual)