1. The Cell Cycle:
Process in which cells grow, prepare for division, and divides to form two daughter cells.
Reasons cells divide:
1. Size (Surface area to volume ratio)
2. Reproduction ( Asexual vs Sexual)
3. Growth & Development (Multicellular)
4. Repair and Replacement of tissue

2. Cells constantly need to make new cells
Cells constantly need to make new cells. Each new cell must have identical DNA to the old cell. How is this accomplished in living organisms?
THE CELL CYCLE!

3. Cell Cycle & Mitosis
Interphase: a period of growth and preparation for division in cell
Mitosis: the division of the cell nucleus (eukaryotic cells)

4. 1. Fold your paper into 8 boxes

5. 2. Cut your paper down the middle horizontal line

6. 3. Tape the two strips of paper together where the dashed line is

7. 4. Draw the lines and label each section
INTERPHASE
MITOSIS (PMAT)
CYTO-
KINESIS

8. G1 = growth 1 (Interphase)
Cell grows in size
Organelles and proteins made

9. S = synthesis(Interphase)
DNA is replicated (“synthesized”)
Each chromosome duplicates to make a sister chromatid
2x as much DNA at the end of synthesis

10. G2: growth 2 (Interphase)
Continued cell growth
Organelles and molecules needed for division are produced

11. Prophase (Mitosis) Nucleus disappears
Chromosomes condense and become visible
Centrioles move to opposite sides of cell
Spindle starts to form
X X X

12. Metaphase (Mitosis) X X X Chromosomes line up in the middle
Spindle fibers connect centriole to centromere X X X

13. < < < < < < Anaphase (Mitosis)
Sister chromatids separate (break apart) as spindle fibers pull them to opposite sides of cell
Chromatids look like “A”
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14. Telophase (Mitosis) Chromosomes are at opposite sides of the cell
Nuclear membrane reforms
Chromosomes unwind
Spindle breaks apart
Nucleolus visible in each daughter cell
< < <
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15. Cytokinesis: Division of the cytoplasm and organelles
Animal: Division of the cytoplasm and organelles and pinching off into 2 IDENTICAL daughter cells.
Plant: Cell plate forms and creates a new cell membrane to make 2 IDENTICAL daughter cells

16. Cell Cycle Overview

17. Cell Cycle Follow-Up Questions
Homework!