Mitosis and meiosis

1. Mitosis & MeiosisMitosis & Meiosis
Mitosis animation:Mitosis animation:
http://www.youtube.com/watch?v=2WwIKdyBN_s&feature=relatedhttp://www.youtube.com/watch?v=2WwIKdyBN_s&feature=related

2. Mitosis:Mitosis:
If a cell wants to make a duplicate of itself, it first If a cell wants to make a duplicate of itself, it first
must copy its DNA (part of a chromosome).must copy its DNA (part of a chromosome).
The copies then must be separated & sorted into The copies then must be separated & sorted into
two sides of the cell.two sides of the cell.
The cell then splits in two. Part of each parent is The cell then splits in two. Part of each parent is
carried to the two new cells. carried to the two new cells.
Results in cells such as internal organs, skin, bones, Results in cells such as internal organs, skin, bones,
blood, etc. blood, etc.

3. Meiosis:Meiosis:
As in mitosis, if a cell wants to make a duplicate of itself, As in mitosis, if a cell wants to make a duplicate of itself,
it first must copy its DNA (part of a chromosome).it first must copy its DNA (part of a chromosome).
Results in reproductive cells (sperm, eggs, etc). Results in reproductive cells (sperm, eggs, etc).
Part of each parent is carried to the four new cells. Part of each parent is carried to the four new cells.
Meiosis has evolved to solve a problem.Meiosis has evolved to solve a problem.
The problem is this: some organisms have sex with other The problem is this: some organisms have sex with other
organisms – that is, they combine their genes together organisms – that is, they combine their genes together
(creating genetic diversity).(creating genetic diversity).
Why would this be a problem?Why would this be a problem?

4. This may you remember these terms:This may you remember these terms:
MITMITosis takes the cell and osis takes the cell and MMakes akes IIt t TTwo (diploid)wo (diploid)
MMeeiosis has to do with siosis has to do with seexx
From the cell’s point of view:From the cell’s point of view:
 mmITITosis results in osis results in IIdentical dentical TTwinswins
 mmEEioioSSis results in is results in EEgg and gg and SSperm (haploid)perm (haploid)
Clyde Freeman Herreid – Dept. of Biological Sciences: Buffalo State Univ. of New YorkClyde Freeman Herreid – Dept. of Biological Sciences: Buffalo State Univ. of New York

5. Mitosis: Meiosis:Mitosis: Meiosis:

Each resulting cell still has chromosomes from mom & dadEach resulting cell still has chromosomes from mom & dad

6. MitosisMitosis
Mitosis animations:Mitosis animations:

http://www.youtube.com/watch?v=2WwIKdyBN_s&feature=relatedhttp://www.youtube.com/watch?v=2WwIKdyBN_s&feature=related

http://www.youtube.com/watch?v=VlN7K1-9QB0http://www.youtube.com/watch?v=VlN7K1-9QB0

7. VocabularyVocabulary
DiploidDiploid
Haploid Haploid
InterphaseInterphase
ProphaseProphase
MetaphaseMetaphase
Anaphase Anaphase
TelophaseTelophase
CytokinesisCytokinesis

8. Interphase Interphase occurs just before occurs just before
Mitosis begins:Mitosis begins:
DNA is replicated
along with
organelles and
other cellular
components and
the cell prepares
for division.
http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

9. MitosisMitosis Interphase Interphase
Animal cellAnimal cell Plant cellPlant cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

10. 11
stst
step in Mitosis: step in Mitosis:
Prophase (preparation phase)Prophase (preparation phase)
http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm
The DNA recoils,
and the
chromosomes
condense; the
nuclear membrane
disappears, and the
mitotic spindles
begin to form.

11. MitosisMitosis Prophase Prophase
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Animal cellAnimal cell Plant cellPlant cell

12. 22
ndnd
step in Mitosis: step in Mitosis:
metaphase (organizational metaphase (organizational
phase)phase)
The chromosomes The chromosomes
line up the middle line up the middle
of the cell with the of the cell with the
help of spindle help of spindle
fibers attached to fibers attached to
the centromere of the centromere of
each replicated each replicated
chromosome. chromosome.
http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

13. MitosisMitosis Metaphase Metaphase
Animal cellAnimal cell Plant cellPlant cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

14. 33
rdrd
step in Mitosis: step in Mitosis:
Anaphase (separation phase)Anaphase (separation phase)
The chromosomes The chromosomes
split in the middle split in the middle
and the sister and the sister
chromatids are chromatids are
pulled by the pulled by the
spindle fibers to spindle fibers to
opposite poles of opposite poles of
the cell. the cell.
http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

15. MitosisMitosis Anaphase Anaphase
Animal cellAnimal cell Plant cellPlant cell
Photographs from:
http://www.bioweb.uncc.edu/biol1110/Stages.htm

16. 44
thth
step in Mitosis: step in Mitosis:
TelophaseTelophase
The chromosomes, along The chromosomes, along
with the cytoplasm and its with the cytoplasm and its
organelles and membranes organelles and membranes
are divided into 2 are divided into 2
portions. This diagram portions. This diagram
shows the end of telophase.shows the end of telophase.
http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

17. MitosisMitosis Telophase Telophase
Animal cellAnimal cell Plant cellPlant cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

18. After Mitosis:After Mitosis:
CytokinesisCytokinesis
The actual splitting ofThe actual splitting of
the daughter cells the daughter cells
into into
two separate cells is two separate cells is
called cytokinesis andcalled cytokinesis and
occurs differently in occurs differently in
both plant and animalboth plant and animal
Cells.Cells.
Beginning of cytokinesis in a plant:
Beginning of cytokinesis in an animal:
http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

19. nIInterphasenterphase
nPProphaserophase
nMMetaphaseetaphase
nAAnaphasenaphase
nTTelophaseelophase
nCCytokinesisytokinesis
IPMAIPMA
TCTC
II PPrayray MMore ore AAtt TThe he CChurchhurch
Julie Camp’s mitosis power point - http://sciencespot.net/Pages/classbio.html#Anchor-mitosis

20. MeiosisMeiosis

Meiosis animation:Meiosis animation:
http://www.youtube.com/watch?v=D1_-mQS_FZ0&NR=1http://www.youtube.com/watch?v=D1_-mQS_FZ0&NR=1

21. Vocabulary Vocabulary
Diploid Diploid
Haploid Haploid
Germ cellGerm cell
Somatic cellSomatic cell
Interphase Interphase
ProphaseProphase
MetaphaseMetaphase
Anaphase Anaphase
TelophaseTelophase
CytokinesisCytokinesis

23. Meiosis Meiosis InterphaseInterphase
Meiosis is preceded
by interphase. The
chromosomes have
not yet condensed.
http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

24. MeiosisMeiosis Interphase Interphase
The chromosomes
have replicated, and
the chromatin begins to
condense.
http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

25. MeiosisMeiosis Prophase I Prophase I
The chromosomes are
completely
condensed. In meiosis
(unlike mitosis), the
homologous
chromosomes pair
with one another
http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

26. Meiosis Meiosis Metaphase IMetaphase I
The nuclear The nuclear
membrane dissolves membrane dissolves
and the homologous and the homologous
chromosomes attach chromosomes attach
to the spindle fibers. to the spindle fibers.
They are preparing to They are preparing to
go to opposite poles. go to opposite poles.
http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

27. Meiosis Meiosis Anaphase IAnaphase I
The chromosomes The chromosomes
move to opposite move to opposite
ends of the cell. ends of the cell.
http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

28. Meiosis Meiosis Telophase I Telophase I && Cytokinesis Cytokinesis
The cell begins to The cell begins to
divide into two divide into two
daughter cells. It is daughter cells. It is
important to important to
understand that each understand that each
daughter cell can get daughter cell can get
any combination of any combination of
maternal and paternal maternal and paternal
chromosomes. chromosomes.
http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

29. Meiosis Meiosis Prophase IIProphase II
The cell has divided The cell has divided
into two daughter into two daughter
cells. cells.
http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

30. Meiosis Meiosis Metaphase IIMetaphase II
As in Meiosis I, the As in Meiosis I, the
chromosomes line up chromosomes line up
on the spindle fibers. on the spindle fibers.
http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

31. Meiosis Meiosis Anaphase IIAnaphase II
The two cells each The two cells each
begin to divide. As in begin to divide. As in
Meiosis I, the Meiosis I, the
chromosomes move chromosomes move
to opposite ends of to opposite ends of
each cell. each cell.
http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

32. Telophase II Telophase II && CytokinesisCytokinesis
With the formation of With the formation of
four cells, meiosis is four cells, meiosis is
over. Each of these over. Each of these
prospective germ cells prospective germ cells
carries half the carries half the
number of number of
chromosomes of chromosomes of
somatic cells. somatic cells.
http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

33. Yvonne NormanYvonne Norman
G410 (Life Sciences for Middle School Educators)G410 (Life Sciences for Middle School Educators)
Senior – Portland State UniversitySenior – Portland State University
February 2009February 2009