1. Mitosis
What is it?
Why is it Important?
What do YOU need to know? 1

2. Mitosis = Cell Division
Why must cells divide?
The cell theory states:
ALL CELLS ARISE FROM OTHER CELLS…
How is that possible?

3. Why do YOU need it? YOU started out as ONE cell…
Are you STILL one cell?????
If you fall on the pavement and scrape your knee…
Does it heal?
Your stomach acid burns through the stomach lining ever few days…
Are your stomach contents spilling out into your body?

4. Cell Growth Think about a balloon…
What happens when you fill it with too much air?
The same would happen to a cell if it kept growing – from the inside out – without dividing…

5. Cell Repair
You know that EVERY TIME you touch something, you leave skin cells behind…
What happens when you break a bone?
How about when you need to get stiches?

6. YOU ALWAYS NEED NEW CELLS!
Mitosis is the process by which new body cells are formed for growth or repair
THIS type of cell division results in TWO IDENTICAL cells being produced from ONE parent cell
Reproduction involving ONE parent is Asexual Reproduction (aka MITOSIS)

7. Asexual Reproduction (Mitosis)
Happens with single-cell critters
And Multicellular organisms (us!) 7

8. Asexual Reproduction = Mitosis
Mitosis is Asexual Cell Division
It happens in a series of stages…
The stages depend on the type of organism:
Prokaryotic or
Eukaryotic

9. One Cell Becomes Two
The stages of Mitosis begin within one cell (called the Parent Cell)
- The DNA is copied and the cell splits in half
The final product of THIS type of Cell Division is TWO new IDENTICAL cells (called Daughter Cells)
- The Daughter Cells are clones of the Parent Cell

10. Mitosis makes Clones
Mitosis involves a series of changes that make an identical copy of the original cell
- The DNA is copied “exactly”
Mitosis makes a clone of the parent cell
ONE parent cell divides to make TWO identical daughter cells

11. Remember DNA? Deoxyribonucleic Acid
One of two Nucleic Acids you need to know
Why does a cell need it?
- Because DNA contains your hereditary information
- The instructions to make the proteins that MAKE YOU!

12. Mitosis: Prokaryotes Binary Fission
Binary=two pieces/parts Fission=split
Prokaryotes have no nucleus…
Bacteria 12

13. Binary Fission... First, DNA replicates (duplicates)…
- Since Bacteria have no nucleus, the DNA replicates in the cytoplasm 13

14. DNA is replicated
DNA must be replicated (copied) so that each new cell has an EXACT copy of the “instructions” (the hereditary information)
Remember, we are making clones…

15. DNA Separates & The Parent Cell Divides in Two
This division is much simpler, quicker than cell reproduction in Eukaryotes
Cell Division 15

16. Mitosis: Eukaryotes
Animal Cells:
YOU!
Plant Cells 16

17. Different Types Depending on the Organism
Budding
Vegetative Propagation
Mitosis Cycle in the Nucleus (US!)

18. One Cell Becomes Two
In Eukaryotes, the stages of Mitosis begin within the NUCLEUS of the Parent Cell
The final product of THIS type of Cell Division is TWO new Daughter Cells
- The Daughter Cells are identical to the Parent Cell!
* They are clones!

19. Budding A new organism develops as an “outgrowth” of the parent
- A “bud” forms which will grow to be identical to the parent
Hydra - a new individual forms
Yeast budding

20. Budding Cont’d…
Yeast Hydra

21. Vegetative Propagation
In vegetative propagation, a part of a plant (root, stem, leaf) grows into a new plant
The new growth is identical to the parent plant
This is how potatoes, garlic and strawberries are grown

22. Vegetative Propagation
Runners: Strawberry & Spider Plants

23. Vegetative Propagation
Bulbs: Tulips, Daffodils, Garlic and Onions

24. Vegetative Propagation
Tubers/Rhizomes: Potatoes and grasses

25. Mitosis: Eukaryotes
Mitosis begins in the nucleus, where the DNA must duplicate before the cell divides 25

26. “Body” Cells… (aka Somatic Cells)
Mi-TO-sis happens with ALL cells in the body (except sex cells)
- Your TOE is a body part…
- Mi-TO-sis has the word “to” in it… to remind you that it makes two cells!
Mitosis begins in the nucleus
- Remember: The nucleus is in control

27. Advantages of Mitosis
Quick Process
Makes IDENTICAL Copies

28. Disadvantages of Mitosis
Makes IDENTICAL Copies
HUH?????
Didn't we just say that was an ADVANTAGE????

29. Disadvantages of Mitosis
Makes IDENTICAL Copies
THINK… What would this world be like if we were all identical?
THINK…If we were all identical, it would be easy to wipe out humans! (or any organism!)

30. That’s all well and dandy
But, how do all of the organelles and such get copied?
I mean, there’s A LOT of stuff inside a Eukaryotic Cell!

31. Eukaryotic Cell Cycle Cells go through a “cycle” after they are “born”
They only divide when the nucleus tells them to!
The nucleus decides!
The cell cycle is:
“I pee on a mat, see?” 31

32. The Nucleus
All of the action begins and ends with direction from the Nucleus
- The Nucleus is in control
The Chromosomes in the Nucleus contain the genes which control cell activities
- Remember: Your Chromosomes are made up of DNA which is a Nucleic Acid made up of Nucleotides that are found in the Nucleus!

33. Stages of The Cell Cycle
Cells spend most of their time in Interphase
This is the phase where they perform all of their life functions
- (STRANGER-C)
The Stages (Phases) of Mitosis are:
- Prophase
- Metaphase
- Anaphase
- Telophase
- Cytokinesis (only in Animal Cells) I P M A T C?

34. Interphase I
INTERPHASE is the “IN BETWEEN” phase (the period between cell divisions where cell lives)
When it is time to divide, at the end of Interphase, single stranded chromosomes (chromatids) Replicate (make an exact copy)

35. Chromatids condense and duplicate35

36. Chromosomes
The original chromatid is copied and the copy is attached (like velcro) to the original at the Centromere
Centromere
It is now called a Chromosome
Centromere

37. 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

38. Coils up into chromosomes
Chromatin to chromosome illustration
Chromatin
Coils up into chromosomes
Duplicates itself

39. AFTER Interphase…Mitosis
Mitosis is cell division
Mitosis consists of 4 distinct phases:
Prophase
Metaphase
Anaphase
Telophase P M A T

40. 4 phases of nuclear division (mitosis), directed by the cell’s DNA (PMAT)
Prophase
Metaphase—(Middle)
Anaphase—(Apart)
Anaphase—(Apart)
Telophase—(Two)

41. Prophase
In Prophase the double stranded condensed chromosomes become visible
The nuclear membrane disintegrates
In animal cells, the centriole and the spindle fibers move to opposite sides of the cell

42. Metaphase Metaphase is easy to recognize!
The chromosomes move toward the middle of the cell where they line up and prepare for division
Centrioles spit out Spindle Fibers that attach to the middle (centromere) of the chromosome
Meta = Middle

43. Anaphase During Anaphase, the spindle fibers pull the chromatids apart
- Chromosomes split apart
The chromatids move to opposite ends of the cell
Anaphase = Apart
Each chromatid is now a single stranded chromosome containing all of the necessary genetic information

44. Telophase The last official stage of mitosis is Telophase
- (Cytokinesis is also a part of this…but only in the Animal Cell)
In Telophase, the nuclear membrane reappears around each set of chromosomes
- Forming two identical nuclei
Cytokinesis is different for Plant and Animal Cells…

45. Cytokinesis
The last official stage of mitosis is Telophase, but in Animal Cells, one last phase splits the cell into two
- Cytokinesis
- Cyto=Cytoplasm
- Kinesis=Split
Cytokinesis does NOT occur in Plant Cells…

46. Why? What do plant cells have surrounding them that we do not?
______________
The membrane cannot ”pinch in” to create two separate cells
The plant cell needs to “Build A Wall” in the middle of the cell in order for it to split into two
- This is the Cell Plate and it is made of Cellulose

47. Stages of Mitosis (IPMAT,C)

48. Mitosis produces identical offspring (2N2N)48

49. What’s 2N????
aka, Diploid 49

50. N = The number of chromosomes in a Sex Cell
In Sexually producing organisms (US!) the Sex Cell (aka Gamete) is the sperm and the egg
The “N” number, aka Haploid, is the number of chromosomes in each Gamete
- In humans, it is 23 50

51. 2N numbers are Different…
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
Fern = 1260 chromosomes or 630 pairs
Fruit Fly = 8 chromosomes or 4 pairs
Amoeba = 50 chromosomes or 25 pairs
Horse = 64 chromosomes or 32 pairs
Cat = 32 chromosomes or 16 pairs
Carp = 174 chromosomes or 87 pairs
Chicken = 78 chromosomes or 39 pairs
Chromosome number has nothing to do with intelligence! 51

52. The Nucleus is in Control… Right?
The Nucleus controls all cell activities
What happens if the nucleus loses control?
Uncontrolled cell division causes a tumor
THAT is CANCER! 52