1. 10-2 Cell Division
In eukaryotes, cell division occurs in 2 major stages.
Mitosis: cell nucleus divides (exact copy made)
2. Cytokinesis: division of the cell cytoplasm.
Cyto = cell
kinesis = movement
cytoplasm
cytoskeleton
pyrokinesis
telekinesis

2. Chromosomes: How genetic information is passed from one generation to the next.
Before cell division, each chromosome is duplicated (copied).

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Chromosomes
Each chromosome consists of two identical “sister” chromatids.
Each pair of chromatids is attached at an area called the centromere.
Sister chromatids
Photo Credit: © Gunther F. Bahr/AFIP/Stone
Centromere
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4. When the cell divides, the chromatids separate.
Chromosomes
When the cell divides, the chromatids separate.
Each new cell gets one chromatid – which becomes a new chromosome for the new cell

5. Draw and label a chromosome:

6. Draw and label a chromosome:
The “other” Sister Chromatid
Sister Chromatid
centromere
the whole thing
is a chromosome
chromatin
DNA

10. When can you see chromosomes?
Normally the DNA is unraveled as
Chromatin …. BUT

11. During Mitosis you can see the DNA
as chromosomes!!!

12. Mitosis Is divided into four phases: (PMAT) Prophase Metaphase
Anaphase
Telophase 12

13. Bellwork: Fri. Oct. 23, 2015
Draw the dividing plant and animal cells and label the dividing features J
Plant: forms a “cell plate”
Animal: forms a “cleavage furrow”

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What is this?
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15. cleavage

17. Metaphase Interphase Prophase Telophase Anaphase 1 3 2 centrioles
Nuclear membrane
DNA = chromatin
centromere
Sister chromatids
Spindle fiber
Telophase
Anaphase 5 4 17

18. Metaphase Interphase Prophase Telophase Anaphase 1 3 2 centrioles
Nuclear membrane
DNA = chromatin
centromere
Sister chromatids
Spindle fiber
Telophase
Anaphase 5 4 18

20. Cytokinesis in an animal cell

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Cytokinesis in Plants
In plants, a structure known as the cell plate forms midway between the divided nuclei.
Cell plate
Cell wall
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24. The Cell Cycle http://www.biologycorner.com/bio1/cellcycle.html
Animals - cell pinches inward
Plants - a new cell wall forms between the two new cells

25. Bellwork: Mon. Oct. 26, 2015 Do you know the 4 phases of mitosis?
_________ __________ _________ _______
What is the long phase between mitosis?
___________
Prophase
Metaphase
Anaphase
Telophase
Interphase

26. Cell Cycle Notes: Series of events cells go through as they grow
and divide.
Interphase: period of growth that occurs
between cell divisions.

27. During cell cycle: cell prepares for division grows
divides to form 2 daughter cells - each of
which begins the cycle again

28. 1st 3 occur during Interphase:
Cell Cycle = 4 phases –
1st 3 occur during Interphase:
G1 (First Gap Phase)
S Phase
G2 (Second Gap Phase)
M Phase (mitosis)

30. use your ruler to divide one quarter into fifths

31. Now label the Phases of the Cell Cycle
G1 Phase
Now label the Phases of the Cell Cycle
S Phase
Cytokinesis
Telophase
G1, S, G2 are Interphase!!!
Anaphase
Mitosis
Metaphase
G2 Phase
Prophase
PMAT !!!

32. Cell Cycle Cell increases in size &
synthesizes new proteins and organelles
chromosomes are replicated
DNA synthesis takes place
During the cell cycle, the cell grows, replicates its DNA, and divides into two daughter cells. DNA synthesis takes place during the S phase. Cell division takes place during the M phase. G1 and G2 are gap phases.
Organelles & molecules required for cell division made

33. Cell Cycle Cell increases in size &
synthesizes new proteins and organelles
chromosomes are replicated
DNA synthesis takes place
During the cell cycle, the cell grows, replicates its DNA, and divides into two daughter cells. DNA synthesis takes place during the S phase. Cell division takes place during the M phase. G1 and G2 are gap phases.
Organelles & molecules required for cell division made

34. Why Do Cells Divide?
Reproduction
Growth
Repair
Mitosis: nuclear division, number of chromosomes remains the same

35. Skin cells are always “falling off” of us so skin is constantly going through mitosis to replace the lost skin cells

37. http://www.youtube.com/watch?v=LSJKXlK3Lx8 Mitosis – Cell Cycle
What's the difference between identical and fraternal twins?

38. But when you look at a cell it may not be so clearly defined
Cell getting ready to come out of Interphase and move into early prophase
Chromosomes condensing in later prophase
Chromosomes “met” up in the middle during metaphase
During telophase the cell looks like a “telophone”
Sister chromatids being “ripped apart” during anaphase
You can see the “cleavage furrow” right before cytokinesis in later telophase
Most eukaryotic cells go through a regular cycle of interphase, mitosis and cytokinesis. Mitosis has four phases: Prophase, Metaphase, Anaphase and Telophase. The events shown here are typical of animal cells.
But when you look at a cell it may not be so clearly defined

39. Chromosomes (paired chromatids)
Mitosis
Section 10-2
Spindle forming
Prophase
Prophase
Chromosomes (paired chromatids)
Centromere
Most eukaryotic cells go through a regular cycle of interphase, mitosis and cytokinesis. Mitosis has four phases: Prophase, Metaphase, Anaphase and Telophase. The events shown here are typical of animal cells.
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Mitosis
Spindle
forming
Prophase
Prophase is the first and longest phase of mitosis.
The centrioles separate and take up positions on opposite sides of the nucleus.
Centromere
Chromosomes
(paired chromatids)
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Mitosis
Spindle
forming
The centrioles lie in a region called the centrosome.
The centrosome helps to organize the spindle, a fanlike microtubule structure that helps separate the chromosomes.
Centromere
Chromosomes
(paired chromatids)
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42. Chromatin condenses into chromosomes.
Mitosis
Spindle
forming
Chromatin condenses into chromosomes.
The centrioles separate and a spindle begins to form.
The nuclear envelope breaks down.
Centromere
Chromosomes
(paired chromatids)

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Mitosis
Metaphase
Centriole
Spindle
Centriole
Metaphase
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Mitosis
Centriole
Metaphase
The second phase of mitosis is metaphase.
The chromosomes line up across the center of the cell.
Microtubules connect the centromere of each chromosome to the poles of the spindle.
Spindle
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47. Individual chromosomes
Mitosis
Anaphase
Individual chromosomes
Anaphase
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Mitosis
Anaphase
Anaphase is the third phase of mitosis.
The sister chromatids separate into individual chromosomes.
The chromosomes continue to move until they have separated into two groups.
Individual
chromosomes
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50. Nuclear envelope reforming
Mitosis
Telophase
Nuclear envelope reforming
Telophase
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Mitosis
Telophase
Telophase is the fourth and final phase of mitosis.
Chromosomes gather at opposite ends of the cell and lose their distinct shape.
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Mitosis
A new nuclear envelope forms around each cluster of chromosomes.
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Cytokinesis
Cytokinesis
Cytokinesis
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55. During cytokinesis, the cytoplasm pinches in half.
Each daughter cell has an identical set of duplicate chromosomes

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Bellwork: Thurs. Nov. 4, 2010
Series of events cells go through as they grow & divide is called
cell cycle.
mitosis.
interphase.
cytokinesis.
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57. Longest phase in mitosis is prophase. metaphase. anaphase. telophase.
10-2
Longest phase in mitosis is
prophase.
metaphase.
anaphase.
telophase.

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10-2
Longest phase in cell cycle is
interphase.
cytokinesis
prophase
metaphase
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DNA replication takes place during the
S phase of the cell cycle.
G1 phase of the cell cycle.
G2 phase of the cell cycle.
M phase of the cell cycle.
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Bellwork: Thurs. Nov. 4, 2010
During mitosis, “sister” chromatids separate from one another during
telophase.
interphase.
anaphase.
metaphase.
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