1. Lesson Objectives—Cell Cycle
Describe cell division in eukaryotes. Describe the basic properties of chromosomes.
Describe the key steps in the cell cycle.
Identify and describe the main processes in mitosis. .

2. Cell Division
Process by which a cell divides to form new cells (daughter cells)
Three types of cell division
Prokaryotes (bacteria)
Binary fission: divides forming two new identical cells, faster than mitosis,
20 minutes, no involvement of the nuclear envelope and centromeres
Eukaryotes
Mitosis
Body Cells: Somatic cells; Diploid (2n): homologous pair;2 X 23 Chromosomes = 46 chromosomes; 1 cell to 2 cells, exact copy
Meiosis
Sex Cells: Meiosis; gamete cells; haploid; 1n; 1 X 23 Chromosomes = 23 chromosomes, 1 cell to 4 cells; not identical variability

3. Cell Division where multiplication and divide mean the same thing!

4. Why do cells divide? So an organism can grow
Replace dead or worn out cells
Repair cells

5. The core macromolecule of mitosis
DNA (Deoxyribonucleic Acid): genetic material of nearly all organisms
Chromosomes: DNA in a coiled, rod shaped form that occurs during cell division

6. Cell Cycle of Body Cells
Cell cycle is continuous process 1) Cells grow 2) DNA replicated 3) Organelles duplicated 4) Divide to form daughter cells
1: Interphase: (3 Phases; G1, S, G2) ; Period of growth and DNA replication ;
2: Mitosis (4 steps; Prophase, Metaphase, Anaphase, Telophase) Nucleus divides
3: Cytokinesis—Cytoplasm divide, forming 2 cells; each new daughter cell is genetically identical to parent cell

8. Cell Cycle of Body Cells interphase
Interphase: period of growth and DNA replication between cell divisions
Three phases:
G1 Phase, Also *Check point
Cell increases in size
, DNA is in chromatin form (thread like coils)
S Phase, Also *Check point
Replication of chromosomes
Now two strands called sister chromatids joined by a centromere
G2 Phase, Also* Check point
organelles double
new cytoplasm forms
All other structures needed for mitosis form
*A checkpoint is a stage in the eukaryotic cell cycle at which the
cell examines internal and external cues and "decides" whether
or not to move forward with division.
*Once the cell passes the G1 checkpoint and enters S phase,
it becomes irreversibly committed to division.

10. Cell Cycle of Body Cells
G1 phase
M phase
S phase
G2 phase

11. PMAT Mitosis (1)Prophase (2)Metaphase (3)Anaphase (4)Telophase
Process that divides cell nucleus to produce two new nuclei each with a complete set of chromosomes
Continuous process
4 Phases
(1)Prophase
(2)Metaphase
(3)Anaphase
(4)Telophase
PMAT

12. Prophase
1. Chromosomes visible (sister chromatids) 2. Centrioles migrate to the poles (only in animals) 3. Nuclear membrane disappears 4. Spindle forms

13. Metaphase chromosomes line up on the equator of the cell
spindles attach to centromeres

14. Anaphase sister chromatids separate centromeres divide
sister chromatids move to opposite poles

15. Telophase
1. chromosomes uncoil • now chromatin 2. nuclear membranes reform 3. spindle disappears

16. Cytokinesis Occurs at end of Mitosis
--division of the cytoplasm to form 2 new daughter cells
--organelles are divided
-Daughter cells are genetically identical

17. Warm-up

18. Stopped here 1/24

19. Cell Cycle- Review
Interphase                                                             
Prophase                                                             
Metaphase                                                             
Anaphase                                                             
Telophase                                                             

20. Cell Cycle Plants
Interphase                                                             
Prophase                                                             
Metaphase                                                             
Anaphase                                                             
Telophase                                                             

21. Mitosis Activities
Finish mitosis presentation Start mitosis flip-book

22. Mitosis
Name the phases starting at the top

24. Name the phase
Identify X
Identify Y

25. 6. Name the phase

26. . Name the Phase

27. Control of the Cell Cycle
Regulatory proteins called cyclins control the cell cycle at checkpoints:
G1 Checkpoint—decides whether or not cell will divide
S Checkpoint—determines if DNA has been properly replicated
Mitotic Spindle Checkpoint—ensures chromosomes are aligned at mitotic plate

28. Cell Cycle Checkpoints

29. CANCER CELLS
Result of uncontrolled cell division of cells that have lost ability to regulate cell cycle
Reproduce more rapidly than normal cells
Masses formed called ‘tumors’
Can be caused by:
Cell’s DNA is damaged
Radiation
Toxic chemicals
May form a tumor (mass of abnormal cells)

30. Lesson Summary—Cell Cycle
The cell cycle is a repeating series of events, characterizing the life of a eukaryotic cell.
Binary fission is a form of cell division in prokaryotic organisms that produces identical
offspring.
As a eukaryotic cell prepares to divide, the DNA and associated proteins coil into a
structure, known as a chromosome.
The DNA copies during the S phase of the cell cycle, resulting in a chromosome that
consists of two identical chromatids, known as sister chromatids, attached at a region
called the centromere.
Any cell containing two sets of chromosomes is said to be diploid; the zygote forms
from the fusion of two haploid gametes.
The cell cycle has five phases: the first growth (G1) phase, the synthesis (S) phase,
the second growth (G2) phase, mitosis, and cytokinesis.
Mitosis is the division of the nucleus; four distinct phases of mitosis have been
recognized: prophase, metaphase, anaphase, and telophase.
Cytokinesis is the division of the cytoplasm.
The cell cycle is controlled through feedback mechanisms.
Cancer results from uncontrolled cell division, due to the loss of regulation of the cell
cycle.