1. The Cell Cycle

2. Differentiation
How does one cell become not just many cells, but specialized cells, such as heart cells, brain cells, ear cells, stomach cells, etc? This is due to differentiation. At the earliest stage of life, cells are unspecialized, but the DNA inside of them causes them to differentiate, which means they become specialized- each with a different function.

3. Mitosis We all started off as a tiny, single cell. That
cell then underwent a process called
mitosis (cell division)which then created another cell identical to it.

4. After fertilization occurs, mitosis begins

5. A baby slowly grows into an adult
This is a result of cells dividing to make more cells.

6. A plant grows due to cell division as well!

7. Mitosis involves somatic cells
Somatic Cells All body cells are somatic cells- these cells undergo mitosis and are diploid which means they have 46 chromosomes.
Gamete Cells Sperm and egg cells are gamete cells- these cells undergo meiosis and are haploid which means they have 23 chromosomes.

8. Cell Cycle The cell cycle is the regular sequence of
growth and division that cells
undergo.
The cell cycle has three parts: interphase
mitosis
cytokinesis

10. Chromosome
Chromosomes, which contain DNA, are found inside the nucleus in the cell

11. Cells divide to make specialized cells, which make up tissue, which make up organs=organism

12. Interphase The first stage of the cell cycle
It is the period before cell division
During interphase three things happen:
The cell grows to its mature size
It makes a copy of its DNA and organelles
It prepares for mitosis

13. DNA is in tiny thin strands, called chromatin! Cool!

14. The cell spends most of its time in interphase
The cell spends most of its time in interphase. Mitosis takes about an hour to complete. Some cells divide every 24 hours. Cells must wait for a chemical signal before moving on to each phase of the cycle.

15. Mitosis
Mitosis consists of four phases, prophase, metaphase, anaphase, and telophase
Mitosis is the process by which a cell’s nucleus divides to create a daughter cell that is genetically identical to the parent cell
It occurs in somatic cells only
We call the original cell the parent cell and we call the new cell a daughter cell

16. When do your cells undergo mitosis?
When healing injured tissue
During growth- zygote to adulthood
Regular maintenance of the body
For example, stomach cells are in a harsh, acidic environment so they do not live very long and are replaced every few days by new cells through mitosis.

17. 1st Phase of Mitosis:Prophase
The nuclear membrane begins to break down
The chromatin in the nucleus begins to condense and coil, like fishing line around a ball
Since DNA has replicated in interphase, each rod has doubled, each being an exact copy of the other
Spindle fiber forms from the centrioles

18. Prophase

19. 2nd Phase: Metaphase
The chromosomes line up across the center of the cell
Each chromosome attaches to a spindle fiber at its centromere, which holds the chromatids together

20. Sister chromatids are joined at the centromere

21. Metaphase

22. Metaphase
Chromosomes move along the spindle fibers and line up at the equator of the cell

23. 3rd: Anaphase The centromeres split The two chromatids separate
Each chromatid moves along the spindle fiber to opposite ends of the cell
The cell stretches out

24. Anaphase
Chromosomes begin to pull apart and move to opposite ends of the cell

25. 4th Phase:Telophase
The chromosomes begin to stretch out and lose their rod like structure
This occurs in two regions at the ends of the cell
A new nuclear membrane forms around each chromosome

26. Telophase

27. A Summary of Mitosis

28. Cytokinesis
The cell membrane pinches in around the middle of the cell, eventually splitting in two
Each daughter cell ends up with the same number of identical chromosomes and about half of the organelles and cytoplasm

29. Cytokinesis
Division of the cytoplasm and organelles

30. Cytokinesis

31. Mitosis in Order

32. Plant cell cytokinesis
A plant cell does not divide in the same way as the animal cell because its cell wall is too rigid to squeeze together the way the animal cell does
Instead a cell plate forms in the middle of the cell (made of sticky carbohydrate)
The cell plate gradually develops into a cell membrane, then a cell wall develops

33. Plant Cell Cytokinesis

34. Note Check What are the three phases of the cell cycle?
What are the four phases, in order, of mitosis?
In which phase does DNA replicate?
In your own words what is mitosis?
Why are the daughter cells genetically identical to the parent cell in mitosis?

35. Not all cells undergo Mitosis!
Brain cells
Heart cells
Inner ear cells
These cells do not divide once the organ is formed in humans. If we lose these critical cells, we have to rely on the ones that are left.

36. Cancer
Any substance that is known to cause cancer is called a carcinogen
Cancer can be caused by genetic factors, environmental factors, and /or a unhealthy diet
Cancer occurs when a mutation occurs in the DNA
The cell no longer follows the “check point rules” of the cell cycle

37. Cancer
Cancer cells can be thought of as “bully” cells, they don’t play by the rules
They divide uncontrollably, invading the space of other cells so that they no longer can survive
A tumor results from a mass of cells
Benign tumors are in a way “good” because they are localized and are easy to remove (in the brain they can cause permanent damage if they press on near by brain tissue- even if removed)
Malignant tumors are “bad” as they are able to spread throughout the body and are more difficult to treat

39. What phase am I?

40. What phase am I?
Metaphase!

41. Which phase am I?
Anaphase!

42. How about me?

43. Which Phase am I ?
Telophase!

44. And what phase am I in?

45. Name the phases of mitosis in correct order
Prophase
Metaphase
Anaphase
telophase

46. What is a daughter cell?

48. Cell Cycle Quiz The three parts of the cell cycle, in order are:
interphase, mitosis, cytokinesis
Mitosis, interphase, cytokinesis
Cytokinesis, interphase, mitosis
None of the above

49. 2. The process by which cells divide and make cells with identical chromosomes is called:
Interphase
Meiosis
Mitosis
centromere

50. 3. What phase of mitosis am I in?

51. 4. Sister chromatids (identical chromosomes) attach to________at their centromeres.
Spindle fibers

52. 5. The identical cell created as a result of mitosis is called a_______.
Son cell
Parent cell
Lovely cell
Daughter cell