1. CELL CYCLE
Mitosis

2. DNA
The cells genetic information is carried by the chromosomes which are formed by proteins and DNA.
The cells of all organisms have a specific number of chromosomes, for example:
Fruit flys have 8 chromosomes
Humans have 46 chromosomes

3. DNA (cont.)
In order for the DNA to fit inside the nucleus, it must compact itself by coiling
When DNA is unwound, it is in long, thin strands called chromatin
When the DNA is completely compacted it is in the form of chromosomes and becomes visible under a microscope

4. Chromosomes Before cellular division, each chromosome replicates
Each chromosome is made up of two identical sister chromatids joined by a centromere
When the cell divdes, the sister chromatids separate and each one passes into one of the two new cells

5. Cell Cycle
Period from the beginning of one cell division to the beginning of the next cell division
Divided into 2 parts:
Interphase
Cell Division

6. Cell Cycle
Cell Cycle
Interphase
Cell Division

7. Interphase Occurs between cell divisions
Cell prepares all the materials necessary for cell growth and prepares it for division
Accounts for 90% of the total time in the cell cycle
Divided into 3 stages: G1 S G2

8. Cell Cycle
Cell Cycle
Interphase
Cell Division G1

9. G1
Also known as Gap 1
Characterized by growth and development

10. Cell Cycle
Cell Cycle
Interphase
Cell Division G1 S

11. S Also known as the synthesis phase
Once the cell enters the S phase it is committed to cell division
Chromosomes in the nucleus replicate

12. Cell Cycle
Cell Cycle
Interphase
Cell Division G1 S G2

13. G2
Also known as Gap 2
This is the shortest of the 3 phases in interphase
Cell makes organelles and other materials
Centrioles replicate to form 2 pairs

14. Cell Division Splitting of one cell to form 2 cells
Divided into 2 parts:
Mitosis
Cytokinesis

15. Cell Cycle Cell Cycle Interphase Cell Division G1 S G2 Mitosis
Cytokinesis G1 S G2

16. Mitosis
Process during which a cell’s nucleus divides into two identical nuclei
It is divided into 4 phases:
Prophase
Metaphase
Anaphase
Telophase

17. Cell Cycle Cell Cycle Interphase Cell Division G1 S G2 Mitosis
Cytokinesis G1 S G2
Prophase
Metaphase
Anaphase
Telophase

18. Prophase Cromatin condenses
Proteins form microtubules which form a fibrous structure called the mitotic spindle
Spindle stretches out between opposite poles of the cell
Nuclear envelope and nucleolus break down
Centromere attaches to spindle fibers
Fibers move chromatids to center of cell

19. Metaphase Chromosomes are pulled to center of cell
Chromosomes line up on an imaginary line called the metaphase plate
ALIGNMENT IS CRUCIAL TO ENSURE THAT EACH CELL GETS A COMPLETE SET OF CHROMOSOMES

20. Anaphase Centromeres divide
Spindle fibers pull chromatids toward opposite poles
Ends when chromosomes are at opposite ends of the cell

21. Telophase 2 daughter nuclei form
Nuclear envelopes form around each set of chromosomes
Nucleoli appear
Chromosomes uncoil to form chromatin
Mitotic spindle disassembles

22. Cytokinesis
Process in which the cell’s cytoplasm divides to make 2 daughter cells
Each daughter forms around 1 of the 2 nuclei produced during mitosis
Begins during telophase

23. Cytokinesis in Animal Cells
The cell membrane, at the center of the cell, folds inward to form a cleavage furrow
The cell continues to pinch in half at the furrow until the membrane meets and forms a division resulting in 2 cells with complete cell membranes

24. Cytokinesis in Plant Cells
In plant cells, a cell plate forms between the two new nuclei and then a cell wall forms around it