1. Competencies
1. characterize the phases of the cell cycle and their control points - STEM_BIO11/12-Id-f-6
2. describe the stages of mitosis/meiosis given 2n=6- STEM_BIO11/12-Id-f-7
3. explain the significance or applications of mitosis/meiosis- STEM_BIO11/12-Id-f-9

2. MITOSIS

3. Short Video Clip Guide Questions: 1. What is mitosis. 2
Short Video Clip Guide Questions: 1. What is mitosis? 2. What are the stages of Mitosis? 3. What happens in every stage of mitosis? 4. What is the importance of mitosis?

5. 10X Magnification of Stained Human Cheek Cells

6. Parts of the Human Cheek Cell at 40X Magnification

7. Can you name these parts of the Human Cheek Cell?

8. Centrioles
: Nuclear division

9. CELL DIVISION – Mitosis
Cell Life Cycle
– series of changes a cell goes through from time it is formed until it divides.
Two Events: 1. Cytokinesis
– division of cytoplasm
2. Karyokinesis
– division of nucleus

10. 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
2 Daughter Cells
Parent Cell

11. Many organisms, especially unicellular organisms, reproduce by means of cell division – called asexual reproduction – Ex: bacteria

12. DNA
DNA is located in the nucleus and controls all cell activities including cell division
Long and thread-like DNA in a non-dividing cell is called chromatin
Doubled, coiled, short DNA in a dividing cell is called chromosome
Consists of 2 parts: chromatid and centromere

13. 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

14. 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

15. 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

16. STAGES OF MITOSIS IN WHITEFISH BLASTULA

17. - Accumulation of materials.
Stages:
Interphase
– resting stage
– preparatory stage.
- Accumulation of materials.

18. During Interphase DNA replicates which must occur before Mitosis can begin .

19. 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

20. CELL CYCLE

21. Interphase
This cell is shown, as this is how all cells look before mitosis. Please be aware that Interphase is a phase of the cell cycle, but NOT a stage of mitosis.

22. Prophase
– Chromatin threads coil and shorten and visible bar-like bodies called chromosomes appear.
- each chromosomes is made up of two strand – Chromatid held by a button-like – Centromere.
- centriole separate and move to poles directing to the assembly of mitotic spindle.
- by end of prophase nuclear membrane and nucleoli broke down and disappearance attached to spindle fiber by centromere.

23. Mitosis - Early Prophase
To begin mitosis, the nuclear membrane breaks down, while the chromosomes shorten and thicken (here, a chromosome is two chromatids, bound at a point called the centromere, making an "X" shape). The other structures important for mitosis are also forming (i.e. the centrioles).

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

25. 3. Metaphase – short stage
– chromosomes aligned at the center of the spindle are attached into it.

26. Mitosis - Metaphase
The spindle has now formed and the nuclear membrane has broken down. The chromosomes are lined up along the cell's center and are attached to the spindle fibers. When the individual chromatids (½ of the "X") are separated from the chromosome (the "X"), they are now each referred to as a chromosome

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

30. Anaphase
– centromere split and chromatids move slowly apart towards the end of poles.

31. Mitosis - Anaphase
The newly formed chromosomes are pulled along the spindle toward opposite poles of the cell.

33. The X is pointing to what structure?

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

35. 5. Telophase
– prophase in reverse.
- chromosomes at poles uncoil to become thread like chromatin again.
- Spindle break down and disappear.
- Nuclear membrane forms around each chromatin mass and nucleoli appear in each daughter nuclei.

36. Mitosis - Telophase
The chromosomes have finished their migration to the poles. The spindle has broken down and disappeared. The cell membrane pinches in (forms a cleavage furrow) along the center creating two separate cells . At this time, the chromosomes uncoil and become less visible (as they are during Interphase), the nuclear membrane reforms. The division of the cytoplasm is called cytokinesis. The division of the nucleus is Mitosis. At the end of Telophase, the cell reenters Interphase.

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

39. View of onion root tip under low power

40. MITOSIS – ONION ROOT TIP
Interphase
Prophase
Later Prophase
Metaphase
Early Anaphase
Anaphase
Telophase
Later Telophase

44. Summary: Cell Cycle
Interphase Mitosis (PMAT) Cytokinesis
When cells become old or damaged, they die and are replaced with new cells

45. What is the importance of Mitosis?
1. Qualitative - daughter cells are exactly the same with the mother cells.
2. Quantitative - equal distribution of hereditary units.

46. Why do cells need to divide?
Living things grow by producing more cells, NOT because each cell increases in size
Repair of damaged tissue
If cell gets too big, it cannot get enough nutrients into the cell and wastes out of the cell

47. 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

48. Benign tumors are not cancerous – these cells do not spread to other parts of the body
Malignant tumors are cancerous – these cells break loose and can invade and destroy healthy tissue in other parts of the body (called metastasis)

50. Cancer is not just one disease, but many diseases – over 100 different types of cancers

52. Application Give the important event happening in each stage/phase

53. 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
Chromosomes line up in the middle
Spindle fibers connect to chromosomes
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