1. Cell prepares to reproduce
Mitosis
Cell prepares to reproduce

5. Cell Cycle

6. How do little elephants grow up to be BIG elephants?

7. Why do animals shed their skin?

8. What happens after a sperm fertilizes an egg?

9. In this time-lapse video of cell division in a newt lung cell, you can see a process that normally takes more than an hour occur in less than a minute.

10. Cell division Cell division is vital for all living organisms.
This is the only process that can create new cells.
Cell division always involves two main processes:
the division of the nuclear contents
the division of the cytoplasmic contents
2 Cytoplasms
2 Nuclei

11. Cell Division
Cell Division — process by which a cell divides into 2 new cells
Why do cells need to divide?
Living things grow by producing more cells, NOT because each cell increases in size
Repair of damaged tissues and cells
If cell gets too big, it cannot get enough nutrients into the cell and wastes out of the cell

12. Examples of tissue and cell repair

13. 2 Daughter Cells Parent Cell
The original cell is called the parent cell; 2 new cells are called daughter cells
Before cell division occurs , the cell replicates (copies) all of its DNA, so each daughter cell gets complete set of genetic information from parent cell
Each daughter cell is exactly like the parent cell – same kind and number of chromosomes as the original cell
Mitosis is part of the cell cycle
2 Daughter Cells
Parent Cell

14. DNA
Where is DNA located in the cell?
DNA is located in the nucleus and controls all cell activities including cell division
when the cell is about to divide they are coiled into a structure called a chromosome
Long and thread-like DNA in a non-dividing cell is called chromatin

15. 2 identical “sister” chromatids attached at an area in the middle called a centromere
When cells divide, “sister” chromatids separate and 1 goes to each new cell

16. Coils up into chromosomes
Chromatin to chromosomes illustration:
Chromatin
Coils up into chromosomes
Duplicates itself
Why does DNA need to change from chromatin to chromosome?
More efficient division

17. News of the day! Newest commercially cloned puppy!

18. Chromosome number
Every organism has its own specific number of chromosomes
Examples: Human = 46 chromosomes or 23 pairs
Dog = 78 chromosomes or 39 pairs
Goldfish = 94 chromosomes or 47 pairs
Lettuce = 18 chromosomes or 9 pairs

19. All somatic (body) cells in an organism have the same kind and number of chromosomes
Examples: Human = 46 chromosomes
Human skin cell = 46 chromosomes
Human heart cell = 46 chromosomes
Human muscle cell = 46 chromosomes
Fruit fly = 8 chromosomes
Fruit fly skin cell = 8 chromosomes
Fruit fly heart cell = 8 chromosomes
Fruit fly muscle cell = 8 chromosomes

21. Cell Cycle -- series of events cells go through as they grow and divide
Cell grows, prepares for division, then divides to form 2 daughter cells – each of which then begins the cycle again

22. Interphase—period of cell growth and development
DNA replication (copying) occurs during Interphase
During Interphase the cell also grows, carries out normal cell activities, replicates all other organelles
The cell spends most of its life cycle in Interphase
Interphase is broken down in 3 phases
G1 phase
S phase (synthesis)
G2 phase

24. Mitosis – division of the nucleus into 2 new ones, each with the same number of chromosomes
Mitosis occurs in all the somatic (body) cells
Why does mitosis occur?
So each new daughter cell has nucleus with a complete set of chromosomes

25. Prophase Anaphase—(Apart) Anaphase—(Apart) Telophase—(Two)
4 phases of nuclear division (mitosis), directed by the cell’s DNA (PMAT)
Prophase
Metaphase—(Middle)
Anaphase—(Apart)
Anaphase—(Apart)
Telophase—(Two)

26. Prophase Chromosomes coil up Nuclear envelope disappears
Spindle fibers form

27. Metaphase—(Middle) Chromosomes line up in middle of cell
Spindle fibers connect to chromosomes

28. Anaphase—(Apart) Chromosome copies divide
Spindle fibers pull chromosomes to opposite poles

29. Telophase—(Two) Chromosomes uncoil Nuclear envelopes form
2 new nuclei are formed
Spindle fibers disappear

30. In plant cells a cell plate forms
Cytokinesis — the division of the rest of the cell (cytoplasm and organelles) after the nucleus divides
In animal cells the cytoplasm
pinches in
In plant cells a cell plate forms
After mitosis and cytokinesis, the cell returns to Interphase to continue to grow and perform regular cell activities

32. Summary: Cell Cycle http://www.cellsalive.com/mitosis_js.htm
Interphase Mitosis (PMAT) Cytokinesis
When cells become old or damaged, they die and are replaced with new cells

34. Prophase
Anaphase
Telophase
Interphase
Metaphase

35. Cell cycle Review Tasks
SL:
Textbook pages:
cell division and mitosis practice sheet
Gizmo: complete gizmos on our class page, see me for username and password
Kahoot: eId=1ee26817-e71c-4c98-a062-3d2409b82620#quiz/72e531a5-ca9c-48d4-9f0c- 5a3d8ad3f985/done

37. Why are cells important?

38. Cell division is so essential to your life that it will take place in your body in your lifetime over times!!!!!
Like all split ups its not easy, it is going to maybe be a little messy, there is a lot of drama, and it does take a surprisingly long amount of time for cell division.

39. Quick Task
There are some cells that speed through G1 (interphase) very quickly and don’t spend much time, if any, performing specialized functions before they divide again. Can you guess what type of cells these would be?

40. Quick Task
What occurs if replication errors are left undetected and unfixed before mitosis?

41. Cell Division Control
DNA controls all cell activities including cell division
Some cells lose their ability to control their rate of cell division – the DNA of these cells has become damaged or changed (mutated)
These super-dividing cells form masses called tumors

44. Cancer = uncontrolled cell division
Cancer is not just one disease, but many diseases – over 100 different types of cancers

45. Chromosome Appearance & Location
Phase
Chromosome Appearance & Location
Important Events
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
DNA replication, cell grows and replicates organelles
DNA copies itself; chromatin
Nuclear envelope disappears, spindle fibers form
Chromosomes coil up
Spindle fibers connect to chromosomes
Chromosomes line up in the middle
Spindle fibers pull chromosome copies apart to opposite poles
Chromosome copies divide and move apart
Nuclear envelopes reform, 2 new nuclei are formed, spindle fibers disappear
Chromosomes uncoil back into chromatin
Division of the rest of the cell: cytoplasm and organelles
Chromatin

46. Cell cycle and cancer Review Tasks
Things that you should have completed before the test!
Workbook: pages 6-13, pages (cell cycle and cancer)
Textbook pages: read 20-37
cell division and mitosis flap book
Additional resources:
Gizmo: complete gizmos on our class page, see me for username and password
Work on your word definitions: interphase (G1,S,G2), DNA replication, mitosis, prophase, metaphase, anaphase, telophase, cytokinesis, parent cell, daughter cells, DNA, nuclear envelope, spindle fibres, centrioles, chromatin, sister chromatids, chromosomes, tumour, mutation, cancer