1. Cell Cycle & Mitosis

2. What is the Cell Cycle? All of the steps of a cells life!
There are two basic parts of the cell cycle:
Interphase
A period of growth between divisions.
Cell Division
Mitosis
Cytokinesis

3. What are the phases of the Cell Cycle?
Interphase: A period of growth between divisions.
G1 Phase – Time when cell grows to full size
S Phase – Time when cell replicates DNA
G2 Phase – Time when cell duplicates its organelles
G0 Phase – Time when cell leaves cell cycle (not all cells do this. Example: Nerves)

4. Phases Continued
M – Phase (Mitosis) – Nuclear Division, the cell divides its chromosomes between two cells
Cytokinesis – the cytoplasm actually divides to make two new cells.

5. Fill Out the Pie! Start at the Star! (M) Mitosis – Nuclear Division
(C) Cytokinesis – Cytoplasm Divides
= Interphase – Period of growth between divisions
(Cell spends 90% of its time in interphase) M C
G2 Phase
G1 Phase
Cell Duplicates organelles
S Phase
DNA Replicates
Cell starts initial growth
Start at the Star!
G0 Phase
Cell Doesn’t Divide

6. Mitosis
Prophase
Metaphase
Anaphase
Telophase

7. Review the Cell Cycle!
Interphase: A period of growth between divisions.
G1 Phase – Time when cell grows to full size
S Phase – Time when cell replicates DNA
G2 Phase – Time when cell duplicates its organelles
G0 Phase – Time when cell leaves cell cycle (not all cells do this. Example: Nerves)
M – Phase (Mitosis) – Nuclear Division, the cell divides its chromosomes between two cells
Cytokinesis – the cytoplasm actually divides to make two new cells.

8. Mitosis What is Mitosis? Why does mitosis happen?
Nuclear Division, the cell divides its chromosomes between two cells
Why does mitosis happen?
So that each daughter cell has exactly the same DNA as the parent cell.
How long does it take for mitosis to happen?
10% of a cell’s life cycle (so it depends on the cell type.)

9. How does mitosis Happen?
Prophase – The “Prepare” Phase
Nucleus Vanishes
Spindle Sets Up
Spindle Moves the chromosomes around
Chromosomes form
Centrioles
Nucleus Vanishing
Chromosomes Winding

10. What is a Chromosome?
A chromosome is a piece of DNA that is tightly wound around proteins.
What does a chromosome look like?
A eukaryotic chromosome (like yours) is X shaped. A prokaryotic chromosome (like bacteria) is a loop.

11. Chromosome Parts S I T E R CH OM A D
Sister chromatids – the identical “legs” of the chromosome
Centromere – holds the sister chromatids together.
Centromere

12. How does mitosis happen?
Metaphase – The “Middle” Phase
Chromosomes line up in the middle of the cell.
spindle
Chromosome

13. How does mitosis happen?
Anaphase – the “Away” Phase
Sister Chromatids move away from each other to opposite sides of the cell.
Spindle
Sister Chromatid

14. How does mitosis happen?
Telophase – “The End” Phase
Nucleus reappears
Spindle Disassembles
Chromosomes Unwind
Nucleus
Chromosomes Unwind

15. ReCap! Mitosis – Makes 2 Identical Daughter Cells Other mnemonics:
Prophase - Prepare
Metaphase – Middle
Anaphase – Away
Telophase – The End
Other mnemonics:
PMAT
Phil Makes Awesome Twinkies

16. What happens after mitosis is finished?
6. Answer: Cytokinesis!
7. What is cytokinesis? Cytokinesis is the splitting of the cytoplasm to make daughter cells.

17. How does cytokinesis work?
Plants: Plant cells rebuild the cell wall. The partially finished cell wall is called a cell plate.
Animals: Animal cells pinch in the cell membrane forming a cleavage furrow until both sides of the membrane meet, which separates the cells.
Cell Plate
Cleavage Furrow