The document describes the process of cell division through mitosis. It begins with cells in interphase, where the cell grows and duplicates its DNA in S phase. The cell then enters prophase of mitosis, where the chromosomes condense and spindle fibers form. In metaphase, the chromosomes align along the center of the cell. In anaphase, the sister chromatids are separated and moved to opposite poles by spindle fibers.

1. Biology is the only subject
in which multiplication is
the same thing as division…
AP Biology 2007-2008

2. The Cell Cycle:
Cell Growth, Cell Division
AP Biology 2007-2008

3. Where it all began…
You started as a cell smaller than
a period at the end of a sentence…
AP Biology

4. And now look at you…
How did you
get from there
AP Biology to here?

5. Getting from there to here…
 Going from egg to baby….
the original fertilized egg has to divide…
and divide…
and divide…
and divide…
AP Biology

6. Why do cells divide?
 For reproduction
 asexual reproduction
 one-celled organisms
 For growth
 from fertilized egg to
multi-celled organism
amoeba
 For repair & renewal
 replace cells that die
from normal wear & QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
tear or from injury
AP Biology

7. Making new cells
 Nucleus
 chromosomes
 DNA
 Cytoskeleton
 centrioles
 in animals
 microtubule
spindle fibers
AP Biology

8. DNA
Nucleus
 Function chromosome
protects DNA
 histone protein
 Structure
 nuclear envelope
 double membrane
 membrane fused in spots to create pores
 allows large macromolecules to pass through
nuclear
pores
nuclear
pore
What kind of
molecules need to
pass through? nucleolus
AP Biology nuclear envelope

9. AP Biology

10. Cytoskeleton
 Function
 structural support
 maintains shape of cell
 provides anchorage for organelles
 protein fibers
 microfilaments, intermediate filaments, microtubules
 motility
 cell locomotion
 cilia, flagella, etc.
 regulation
 organizes structures
& activities of cell
AP Biology

11. Cytoskeleton
 actin
 microtubule
 nuclei
AP Biology

12. Centrioles
 Cell division
 in animal cells, pair of centrioles
organize microtubules
 spindle fibers
 guide chromosomes in mitosis
AP Biology

13. End of the Tour
AP Biology

14. Getting the right stuff
 What is passed on to daughter cells?
 exact copy of genetic material = DNA
 mitosis
 organelles, cytoplasm, cell membrane,
enzymes
 cytokinesis
chromosomes (stained orange)
in kangaroo rat epithelial cell
→notice cytoskeleton fibers
AP Biology

15. I.P.M.A.T.
Overview of mitosis
interphase prophase (pro-metaphase)
cytokinesis
AP Biology
metaphase anaphase telophase

16. Interphase
 90% of cell life cycle
 cell doing its “everyday job”
 produce RNA, synthesize proteins/enzymes
 prepares for duplication if triggered
I’m working here!
Time to divide
& multiply!
AP Biology

17. M
Mitosis
Cell cycle G2
Gap 2
G1
 Cell has a “life cycle” Gap 1
G0
cell is formed from S Resting
a mitotic division Synthesis
cell grows & matures cell grows & matures
to divide again to never divide again
G1, S, G2, M liver cells G1→G0
epithelial cells, brain / nerve cells
blood cells, muscle cells
stem cells
AP Biology

18. Interphase
 Divided into 3 phases: G0
 G1 = 1st Gap (Growth)
 cell doing its “everyday job”
o  cell grows
n al te
sig ivid  S = DNA Synthesis
d
 copies chromosomes
 G2 = 2nd Gap (Growth)
 prepares for division
 cell grows (more)
 produces organelles,
proteins, membranes
AP Biology

19. green = key features
Interphase
 Nucleus well-defined
 DNA loosely packed in
long chromatin fibers
 Prepares for mitosis
 replicates
chromosome
 DNA & proteins
 produces proteins &
organelles
AP Biology

20. S phase: Copying / Replicating DNA
 Synthesis phase of Interphase
 dividing cell replicates DNA
 must separate DNA copies
correctly to 2 daughter cells
 human cell duplicates ~3 meters DNA
 each daughter cell gets complete
identical copy
 error rate = ~1 per 100 million bases
 3 billion base pairs in mammalian
genome
 ~30 errors per cell cycle
 mutations (to somatic (body) cells)
AP Biology

21. ACTGGTCAGGCAATGTC
DNA
Organizing DNA
 DNA is organized in
chromosomes histones
 double helix DNA molecule
 wrapped around histone
proteins
 like thread on spools
 DNA-protein complex =
chromatin chromatin
 organized into long thin fiber
 condensed further during
mitosis
double stranded chromosome
AP Biology duplicated mitotic chromosome

22. Copying DNA & packaging it…
 After DNA duplication, chromatin condenses
 coiling & folding to make a smaller package
DNA mitotic chromosome
chromatin
AP Biology

23. double-stranded
mitotic human
chromosomes
AP Biology

24. Mitotic Chromosome
 Duplicated chromosome
 2 sister chromatids
 narrow at centromeres
 contain identical
copies of original DNA
homologous homologous
chromosomes chromosomes
sister chromatids
single-stranded
AP Biology double-stranded homologous = “same information”

25. Mitosis
 Dividing cell’s DNA between
2 daughter nuclei
 “dance of the chromosomes”
 4 phases
 prophase
 metaphase
 anaphase
 telophase
AP Biology

26. green = key features
Prophase
 Chromatin condenses
 visible chromosomes
 chromatids
 Centrioles move to opposite
poles of cell
 animal cell
 Protein fibers cross cell to form
mitotic spindle
 microtubules
 actin, myosin
 coordinates movement of
chromosomes
 Nucleolus disappears
 Nuclear membrane breaks down
AP Biology

27. green = key features
Transition to Metaphase
 Prometaphase
 spindle fibers attach to
centromeres
 creating kinetochores
 microtubules attach at
kinetochores
 connect centromeres to
centrioles
 chromosomes begin
moving
AP Biology

28. green = key features
Metaphase
 Chromosomes align
along middle of cell
 metaphase plate
 meta = middle
 spindle fibers coordinate
movement
 helps to ensure
chromosomes separate
properly
 so each new nucleus
receives only 1 copy of
each chromosome
AP Biology

29. AP Biology

30. green = key features
Anaphase
 Sister chromatids separate at
kinetochores
 move to opposite poles
 pulled at centromeres
 pulled by motor proteins
“walking”along microtubules
 actin, myosin
 increased production of
ATP by mitochondria
 Poles move farther apart
 polar microtubules lengthen
AP Biology

31. Separation of chromatids
 In anaphase, proteins holding together sister
chromatids are inactivated
 separate to become individual chromosomes
1 chromosome 2 chromosomes
2 chromatids single-stranded
AP Biology
double-stranded

32. Chromosome movement
 Kinetochores use
motor proteins that
“walk” chromosome
along attached
microtubule
 microtubule
shortens by
dismantling at
kinetochore
(chromosome) end
AP Biology

33. green = key features
Telophase
 Chromosomes arrive at
opposite poles
 daughter nuclei form
 nucleoli form
 chromosomes disperse
 no longer visible under
light microscope
 Spindle fibers disperse
 Cytokinesis begins
 cell division
AP Biology

34. Cytokinesis
 Animals
 constriction belt of
actin microfilaments
around equator of cell
 cleavage furrow forms
 splits cell in two
 like tightening a draw
string
AP Biology

35. Cytokinesis in Animals
(play Cells Alive movies here)
(playBiology
AP Thinkwell movies here)

36. Mitosis in whitefish blastula
AP Biology

37. Mitosis in animal cells
AP Biology

38. Cytokinesis in Plants
 Plants
 cell plate forms
 vesicles line up at
equator
 derived from Golgi
 vesicles fuse to form
2 cell membranes
 new cell wall laid
down between
membranes
 new cell wall fuses
with existing cell wall
AP Biology

39. Cytokinesis in plant cell
AP Biology

40. Mitosis in plant cell
AP Biology

41. onion root tip
AP Biology

42. Origin of
replication
Evolution of mitosis
chromosome:
 Mitosis in double-stranded replication
DNA of DNA
eukaryotes
likely evolved from
binary fission in elongation of cell
bacteria
 single circular ring of
proteins
chromosome
 no membrane-
bound organelles
cell pinches
in two
AP Biology

43. prokaryotes
(bacteria)
Evolution of
mitosis protists
dinoflagellates
 A possible
progression of
mechanisms protists
diatoms
intermediate
between binary
fission & mitosis eukaryotes
yeast
seen in modern
organisms
eukaryotes
animals
AP Biology

44. Dinoflagellates
 algae
 “red tide”
 bioluminescence
AP Biology

45. Diatoms
 microscopic algae
 marine
 freshwater
AP Biology

46. Any Questions??
AP Biology 2007-2008

47. Ghosts of Lectures Past
(storage)
AP Biology 2007-2008

48. Control of Cell Cycle
AP Biology

49. Kinetochore
 Each chromatid
has own kinetochore
proteins
 microtubules
attach to
kinetochore
proteins
AP Biology

50. Chromosome structure
scaffold chromatin loop
protein
n m
30
DNA nucleosome
histone
rosettes of
chromatin loops
chromosome DNA double helix
AP Biology

51. M
metaphase anaphase
Cell Division cycle prophase telophase
C
G2
 Phases of a dividing
cell’s life interphase (G1, S, G2 phases)
mitosis (M)
 interphase S
cytokinesis (C) G1
 cell grows
 replicates chromosomes
 produces new organelles, enzymes, membranes…
 G1, S, G2
 mitotic phase
 cell separates & divides chromosomes
 mitosis
 cell divides cytoplasm & organelles
 cytokinesis
AP Biology

52. Substitute Slides
for Student Print version
(for student note-taking)
AP Biology 2007-2008

53. And now look at you…
How did you
get from there
AP Biology to here?