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Title: Signals%20and%20Cancer


1
Signals and Cancer
  • http//learn.genetics.utah.edu/content/cells/signa
    ls/

2
1) Look at your photosynthesis data-WHAT does it
mean?-WHY did that happen?-Future
experiments?2) Look at your packet, what are
two ways to graph the data? What is E50?
3
Graph and calculate the rate
4
Warm Up Solve using chi-squareShow work
2.71
df/prob. 0.99 0.95 0.90 0.80 0.70 0.50 0.30 0.20 0.10 0.05
1 0.00013 0.0039 0.016 0.64 0.15 0.46 1.07 1.64 2.71 3.84
2 0.02 0.10 0.21 0.45 0.71 1.39 2.41 3.22 4.60 5.99
3 0.12 0.35 0.58 1.00 1.42 2.37 3.66 4.64 6.25 7.82
4 0.3 0.71 1.06 1.65 2.20 3.36 4.88 5.99 7.78 9.49
5 0.55 1.14 1.61 2.34 3.00 4.35 6.06 7.29 9.24 11.07
5
(No Transcript)
6
Announcements
  • Last days to get stamps on 2A to get FRQ graded
  • Chapters 12-13 reading notes due this week
  • Photosynthesis lab due March 1

7
onion root tipslides are the control, handout is
treated with caffeine
8
Control
Trial Interphase Prophase Metaphase Anaphase Telophase
1
2
Hypothesis
If we look at a 100 cells then____________________
____
Caffeine
Trial Interphase Prophase Metaphase Anaphase Telophase
1
Null Hypothesis If we compare an onion grown
normally and in caffeine then____________________
____
9
Agenda
  • Finish mitosis lab counting
  • Calculate chi squared for labcan you accept
    null?
  • Cell Cycle Coloring with Checkpoints (on stamp
    sheet)
  • DNA Replication presentation prep (on stamp
    sheet)

10
External signals
  • Growth factors
  • coordination between cells
  • protein signals released by body cells that
    stimulate other cells to divide
  • density-dependent inhibition
  • crowded cells stop dividing
  • each cell binds a bit of growth factor
  • not enough activator left to trigger division in
    any one cell
  • anchorage dependence
  • to divide cells must be attached to a substrate
  • touch sensor receptors

11
Growth Factors and Cancer
  • Growth factors can create cancers
  • proto-oncogenes
  • normally activates cell division
  • growth factor genes
  • become oncogenes (cancer-causing) when mutated
  • if switched ON can cause cancer
  • example RAS (activates cyclins)
  • tumor-suppressor genes
  • normally inhibits cell division
  • if switched OFF can cause cancer
  • example p53

12
Cancer Cell Growth
  • Cancer is essentially a failure of cell division
    control
  • unrestrained, uncontrolled cell growth
  • What control is lost?
  • lose checkpoint stops
  • gene p53 plays a key role in G1/S restriction
    point
  • p53 protein halts cell division if it detects
    damaged DNA
  • options
  • stimulates repair enzymes to fix DNA
  • forces cell into G0 resting stage
  • keeps cell in G1 arrest
  • causes apoptosis of damaged cell
  • ALL cancers have to shut down p53 activity

p53 is theCell CycleEnforcer
p53 discovered at Stony Brook by Dr. Arnold Levine
13
p53 master regulator gene
NORMAL p53
p53 allows cells with repaired DNA to divide.
p53 protein
DNA repair enzyme
p53 protein
Step 2
Step 1
Step 3
DNA damage is caused by heat, radiation, or
chemicals.
p53 triggers the destruction of cells damaged
beyond repair.
Cell division stops, and p53 triggers enzymes to
repair damaged region.
ABNORMAL p53
abnormal p53 protein
cancer cell
Step 2
Step 1
Step 3
The p53 protein fails to stop cell division and
repair DNA. Cell divides without repair
to damaged DNA.
DNA damage is caused by heat, radiation, or
chemicals.
Damaged cells continue to divide. If other damage
accumulates, the cell can turn cancerous.
14
Development of Cancer
  • Cancer develops only after a cell experiences 6
    key mutations (hits)
  • unlimited growth
  • turn on growth promoter genes
  • ignore checkpoints
  • turn off tumor suppressor genes (p53)
  • escape apoptosis
  • turn off suicide genes
  • immortality unlimited divisions
  • turn on chromosome maintenance genes
  • promotes blood vessel growth
  • turn on blood vessel growth genes
  • overcome anchor density dependence
  • turn off touch-sensor gene

Its like anout-of-controlcar with manysystems
failing!
15
What causes these hits?
  • Mutations in cells can be triggered by
  • UV radiation
  • chemical exposure
  • radiation exposure
  • heat
  • cigarette smoke
  • pollution
  • age
  • genetics

16
Tumors
  • Mass of abnormal cells
  • Benign tumor
  • abnormal cells remain at original site as a lump
  • p53 has halted cell divisions
  • most do not cause serious problems can be
    removed by surgery
  • Malignant tumor
  • cells leave original site
  • lose attachment to nearby cells
  • carried by blood lymph system to other tissues
  • start more tumors metastasis
  • impair functions of organs throughout body

17
Cancer breast cancer cell mammogram
18
Traditional treatments for cancers
  • Treatments target rapidly dividing cells
  • high-energy radiation
  • kills rapidly dividing cells
  • chemotherapy
  • stop DNA replication
  • stop mitosis cytokinesis
  • stop blood vessel growth

19
New miracle drugs
  • Drugs targeting proteins (enzymes) found only in
    cancer cells
  • Gleevec
  • treatment for adult leukemia (CML) stomach
    cancer (GIST)
  • 1st successful drug targeting only cancer cells

withoutGleevec
withGleevec
Novartes
20
(No Transcript)
21
(No Transcript)
22
  • The mitotic spindle at metaphase
  • Each of the two joined chromatids of a chromosome
    has a kinetochore.
  • Anaphase proteins holding together the sister
    chromatids of each chromosome are inactivated and
    they are now full chromosomes.

23
  • Experimental evidence supports the hypothesis
    that kinetochores use motor proteins that "walk"
    a chromosome along the attached microtubules
    toward the nearest pole.
  • Meanwhile, the microtubules shorten by
    depolymerizing at their kinetochore ends
  • In a dividing animal cell, non
    kinetochore microtubules are responsible for
    elongating the whole cell during anaphase

24
Chromosome movement
  • Kinetochores use motor proteins that walk
    chromosome along attached microtubule
  • microtubule shortens by dismantling at
    kinetochore (chromosome) end

25
Look at the steps of mitosisBook pgs
210-211Write and draw what happens in each part
of mitosisHow is cytokinesis different in
plants and animal? Page 214
  • 10 minutes

26
Announcements
  • Last days to get stamps on 2A to get FRQ graded
  • Chapters 12-13 reading notes due this week
  • Photosynthesis lab due March 1
  • Sub Fridaya friend so be good ?
  • Thanks for the b-day poster period 4 ?

27
Team Whiteboard
  • Cytokinesis in Animals
  • Metaphase
  • Cytokinesis in Plants
  • Prophase
  • Anaphase
  • Telophase

28
(No Transcript)
29
  • The Cell Cycle Clock Cyclins and
    Cyclin-Dependent Kinase
  • Fluctuations in the abundance and activity of
    cell cycle control molecules pace the sequential
    events of the cell cycle.
  • Protein kinases, give the go-ahead signals at the
    G1 and G2 checkpoints
  • The kinases are present at a constant
    concentration in the growing cell, but much of
    the time they are in inactive form.
  • To be active, such a kinase must be attached to a
    cyclin, a protein that gets its name from its
    cyclically fluctuating concentration in the cell.
  • These kinases are called cyclin-dependent
    kinases, or Cdks. The activity of a Cdk rises and
    falls with changes in the concentration of its
    cyclin partner.

Cdks are relatively constant Cyclins vary in the
cycle
30
The stages of mitotic cell division in an animal
cell The light micrographs show dividing lung
cells from a newt, which has 22 chromosomes in
its somatic cells. The chromosomes appear blue
and the microtubules green. (Know the
characteristics of the phases)
31
Review the details of each mitotic phase animal
cells (Know the characteristics of the phases)
Mitosis flash animation (Purves)
32
Cytokinesis divides the cytoplasm How does it
differ in animal and plant cells?
33
  • In animal cells, cytokinesis occurs by cleavage
  • The cleavage furrow, which begins as a shallow
    groove in the cell surface.
  • On the cytoplasmic side, a contractile ring of
    actin microfilaments and molecules of the protein
    myosin
  • The contraction of the dividing cells ring of
    microfilaments is like the pulling of drawstrings

Cytokinesis animation
34
Cytokinesis
  • Cytoplasmic division
  • Animals
  • constriction belt of actin microfilaments around
    equator of cell
  • cleavage furrow forms
  • splits cell in two
  • like tightening a draw string

35
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

36
Going to calculate statistically if a phase is
overrepresented
  • Chi-squared

37
Statistical Test
  • We want to determine if a coin is fair. In other
    words, are the odds of flipping the coin heads-up
    the same as tails-up.
  • We collect data by flipping the coin 200 times.
    The coin landed heads-up 108 times and tails-up
    92 times.
  • At first glance, we might suspect that the coin
    is biased because heads resulted more often than
    tails.
  • To analyze our results use a chi-squared test.

38
  • "The null hypothesis in a chi-square
    goodness-of-fit test states that the sample of
    observed frequencies supports the claim about the
    expected frequencies.  
  • The alternative hypothesis states that there is
    no support for the claim pertaining to the
    expected frequencies."

39
  • Null hypothesis--The coin should be equally
    likely to land head-up or tails-up every time
  • Alternate Hypothesis The coin is rigged and will
    not land equally on heads or tails

40
(No Transcript)
41
  Heads Tails Total
Observed 108 92 200
Expected 100 100 200
Total 208 192 400
The next step is to prepare a table as follows.
  • Chi-squared
  • (108-100)2/100 (92-100) 2/100
  • (8) 2/100 (-8) 2/100
  • 0.64 0.64 1.28

42
Bio uses 0.05
df/prob. 0.99 0.95 0.90 0.80 0.70 0.50 0.30 0.20 0.10 0.05
1 0.00013 0.0039 0.016 0.64 0.15 0.46 1.07 1.64 2.71 3.84
2 0.02 0.10 0.21 0.45 0.71 1.39 2.41 3.22 4.60 5.99
3 0.12 0.35 0.58 1.00 1.42 2.37 3.66 4.64 6.25 7.82
4 0.3 0.71 1.06 1.65 2.20 3.36 4.88 5.99 7.78 9.49
5 0.55 1.14 1.61 2.34 3.00 4.35 6.06 7.29 9.24 11.07
Degrees of freedom by subtracting one from the
number of classes. In this example, we have two
classes (heads and tails), so our degrees of
freedom is 1. Our chi-squared value is
1.28. Because the chi-squared value we obtained
in the coin example is greater than 0.05, we
accept the null hypothesis as true and conclude
that our coin is fair.
43
So for mitosis lab
  • Create null hypothesis about cells treated with
    caffeine vs not treated with caffeine

44
Interpret diagram from notes or book pg 209
45
THE MITOTIC CELL CYCLE The mitotic phase
alternates with interphase in the cell cycle
What are the key parts of each phase?
Mitosis animation
46
(No Transcript)
47
How does our body regulate the cell cycle?
48
Cell Cycle regulation
  • Checkpoints
  • cell cycle controlled by STOP GO chemical
    signals at critical points
  • signals indicate if key cellular processes have
    been completed correctly

49
Checkpoint control system
  • 3 major checkpoints
  • G1/S
  • can DNA synthesis begin?
  • G2/M
  • has DNA synthesis been completed correctly?
  • commitment to mitosis
  • spindle checkpoint
  • are all chromosomes attached to spindle?
  • can sister chromatids separate correctly?

50
G1/S checkpoint
  • G1/S checkpoint is most critical
  • primary decision point
  • restriction point
  • if cell receives GO signal, it divides
  • internal signals cell growth (size), cell
    nutrition
  • external signals growth factors
  • if cell does not receive signal, it exits cycle
    switches to G0 phase
  • non-dividing, working state

51
Go-ahead signals
  • Protein signals that promote cell growth
    division
  • internal signals
  • promoting factors
  • external signals
  • growth factors
  • Primary mechanism of control
  • phosphorylation
  • kinase enzymes
  • either activates or inactivates cell signals

52
Cell cycle signals
inactivated Cdk
  • Cell cycle controls
  • cyclins
  • regulatory proteins
  • levels cycle in the cell
  • Cdks
  • cyclin-dependent kinases
  • phosphorylates cellular proteins
  • activates or inactivates proteins
  • Cdk-cyclin complex
  • triggers passage through different stages of cell
    cycle

activated Cdk
53
Meiosis
54
Bring your grade up. Put in the time to read,
come into office hours, ASK questions
  • Dispatch In YOUR OWN words contrast
  • a) somatic vs gamete
  • b) diploid vs haploid
  • c) homologous chromosome vs chromosome
  • d) meiosis vs mitosis
  • e) chromatid vs chromosome
  • f) allopatric vs sympatric
  • g) depolarization vs polarization
  • h) Meiosis part I vs Meiosis part II
  • i) Evolution vs Hardy-Weinberg

55
  • Evolution is one of the unifying themes of
    biology. Evolution involves change in the
    frequencies of alleles in a population. For a
    particular genetic locus in a population, the
    frequency of the recessive allele (a) is 0.4 and
    the frequency of the dominant allele (A) is 0.6.
  • (a) What is the frequency of each genotype (AA,
    Aa, aa) in this population? What is the frequency
    of the dominant phenotype?
  • (b) How can the Hardy-Weinberg principle of
    genetic equilibrium be used to determine whether
    this population is evolving?
  • (c) Identify a particular environmental change
    and describe how it might alter allelic
    frequencies in this population. Explain which
    condition of the Hardy-Weinberg principle would
    not be met.

56
Battle
  • Metaphase I
  • Metaphase II
  • Prophase I
  • Anaphase II
  • Anaphase I

57
Seat 1
  • Metaphase I

58
Seat 2
  • Anaphase I

59
Seat 3
  • Metaphase II

60
Seat 4
  • Prophase I

61
Any seat
  • Anaphase II

62
Dispatch
  • What are microtubules?
  • What is the role of microtubules in cell
    division?
  • Draw a cell in Metphase I and label
  • -centrioles
  • -microtubules
  • -chromosomes

63
Pick up study guide
  • Answer using only your reading notes

64
What do you know about cytoskeleton?
65
Role of cytoskeleton
  • http//www.youtube.com/watch?v5rqbmLiSkpkfeature
    related
  • http//bio.rutgers.edu/gb101/lab2_mitosis/section
    2_frames.html

66
The mitotic spindle distributes chromosomes to
daughter cells
The assembly of spindle microtubules starts in
the centrosome, known as a microtubule-organizing
center. During interphase, the single centrosome
replicates to form two centrosomes. During
prophase they form spindle fibers and migrate to
the poles.
67
Show the movement of chromosomes
  • -Polar microtubules
  • -Kinetochore microtubules
  • 5 min
  • NEXT FRQ The role of 3 proteins in cell cycle

68
  • http//highered.mcgraw-hill.com/olcweb/cgi/pluginp
    op.cgi?itswf535535/sites/dl/free/0072437316
    /120073/bio14.swfMitosis20and20Cytokinesis

69
Crossing over comic
  • Show homologous pairs crossing over to contribute
    to variation
  • Make it funny
  • Underneath give the academic definition with the
    terms
  • Crossing over
  • Homologous chromosomes
  • Variation
  • 4) Prophase I of meiosis

70
(No Transcript)
71
  • Somatic Cells
  • body cells
  • Ex. ___________
  • Made by mitosis
  • Gametes
  • reproductive cells
  • Ex. ________

72
  • Diploid
  • Having 2 copies of each chromosome (2n), one from
    each parent
  • Somatic cells are diploid
  • Human diploid number is _____
  • Haploid
  • Having only 1 copy of each chromosome (n)
  • Gamete cells are haploid
  • Human haploid number is _____
  • What are the cells in your body that are haploid?

73
Copy and fill in the chart below.
Organism Diploid (in somatic cells) Haploid (in gametes)
Cat 19
Rose 12
Goat 30
Rice 24
Dog 39
Chimpanzee 48
74
  • http//www.wiley.com/college/boyer/0470003790/anim
    ations/protein_folding/protein_folding.htm

75
THE CELL CYCLE Chapter 12
Without counting the G 0 phase, a cell cycle
takes 12-24 hours for most mammalian cells, and
only 20-30 minutes for E. coli cells
76
  • http//highered.mcgraw-hill.com/sites/0072495855/s
    tudent_view0/chapter2/animation__how_the_cell_cycl
    e_works.html
  • Take notes on events of each part of the cell
    cycle
  • Interphase (G1, S, G2) PMATC
  • Follow alleles

77
Get a whiteboard and beads
78
  • Every eukaryotic species has a characteristic
    number of chromosomes in each cell nucleus
  • Somatic (nonreproductive) cells have two sets of
    chromosomes
  • Gametes (reproductive cells sperm and eggs) have
    half as many chromosomes as somatic cells
  • Eukaryotic chromosomes consist of chromatin, a
    complex of DNA and protein that condenses during
    cell division

79
Dispatch
  • Our DNA is 6 feet long, how does it fit into a
    nucleus? Note 10,000 nuclei fit on the tip of
    your pencil. Hint on pg 320-321 or 345

80
(No Transcript)
81
  • http//dnalc.org/view/15491-DNA-packaging-3D-anima
    tion-with-narration.html

82
(No Transcript)
83
Chromosome duplication and distribution during
mitosis. Eukaryotic duplicates each of its
multiple chromosomes before it divides. A
duplicated chromosome consists of two sister
chromatids, which narrow at their centromeres.
84
Cytokinesis in plant cells has no cleavage furrow
During telophase, vesicles derived from the
Golgi apparatus move along microtubules to the
middle of the cell, where they fuse, producing a
cell plate.
85
Mitosis in a plant cell These light micrographs
show mitosis in cells of an onion root.
How does this differ from animal cell mitosis?
86
Mitosis in eukaryotes may have evolved from
binary fission in bacteria
Mitosis video (long)
87
A hypothesis for the evolution of mitosis
Researchers of eukaryotic cell division have
observed in modern organisms what they believe
are mechanisms of division intermediate between
the binary fission of bacteria and mitosis as it
occurs in most eukaryotes.
88
Cancer
  • This man has cancer of the mouth.

89
Regulation of the Cell cycle The timing and rate
of cell division in different parts of a plant or
animal are crucial to normal growth, development,
and maintenance. Do all cells have the same cell
cycle? Why is regulation of the cell cycle of
interest to research?
Cancer Growth Flash animation
90
What is Cancer?
  • Cancer means uncontrolled cell growth
  • The body needs to keep cell growth cell death
  • Cell cycle checkpoints kill mutated or old cells

91
  • http//science.education.nih.gov/supplements/nih1/
    cancer/activities/activity2_animations.htm

92
The cell cycle has traffic lights that serve as
checkpoints
G1 Phase
S Phase
Mitosis
Cytokinesis
G2 Phase
Does the body need more cells?
Is the cell ready for mitosis?
93
Cancer is caused when the checkpoints are broken
and the cell cycle keeps going without stopping
G1 Phase
S Phase
Mitosis
Cytokinesis
G2 Phase
94
What are the types of cancer?
  • Any part of the body can be cancerous
  • Skin cancer
  • Lung cancer
  • Breast cancer
  • Testicular cancer
  • Colon cancer
  • Liver cancer
  • Brain cancer

Lung Cancer
Brain Cancer
95
(No Transcript)
96
How do you get cancer?
  • How can you get cancer?
  • Getting hit in the breast?
  • NO
  • Having unprotected sex?
  • NO
  • Smoking?
  • YES
  • Being in the sun too long?
  • YES

97
Why is cancer so deadly?
  • 1) Mutated cells beat the cell cycle checkpoints
    and keep dividing
  • 2) They form tumors which then stop your body
    parts from functioning normally
  • 3) Angiogensis the tumors hijack blood vessels
    to keep them alive
  • 4) Metastisis the cells from the tumor travel
    and infect other parts of your body

98
Here is the development of colon cancer.
99
Why is Cancer so Hard to Cure?
  • It is a silent killer, by the time it is found it
    is already to late
  • 2) Chemo/Radiation therapy can kill cancer
    cells, but is hard on patients
  • 3) If one cancer cell survives, or travels,
    cancer will come back

100
Can cancer be prevented?
  • Cancer is not contagious.
  • There is no guaranteed way to prevent
    cancer, people can reduce their risk (chance) of
    developing cancer by
  • A) not using tobacco products
  • B) choosing foods with less fat and eating more
    vegetables, fruits, and whole grains
  • C) exercising regularly and maintaining a lean
    weight
  • D) avoiding the harmful rays of the sun, using
    sunblock, and wearing clothing that protects the
    skin

101
Mechanical analogy for the cell cycle control
system In this diagram of the cell cycle, the
flat "stepping stones" around the perimeter
represent sequential events. Like the control
device of an automatic washer.
102
  • Cell Cycle Checkpoints
  • A checkpoint is a critical control point where
    stop and go-ahead signals can regulate the cycle.
  • The G1 checkpoint (the "restriction point) is
    most important.
  • If a cell receives a go-ahead signal at the G1
    checkpoint, it will usually complete the cycle
    and divide.
  • If it does not receive a go-ahead signal at that
    point, it will exit the cycle, switching into a
    non-dividing state called the G0 phase.

G0 (G zero) resting phase
Cell Cycle with Checkpoints Animation
103
Many factors are involved in the regulation of
the cell cycle
104
RB inhibits cell division Active Cdk inhibits RB
105
Cdks are relatively constant Cyclins vary in the
cycle
106
  • The active enzyme and the activating process can
    be inhibited by two families of cell cycle
    inhibitory proteins.
  • Members of the INK4 family bind free CDKs
    thereby preventing association with cyclins.
  • 2. Members of the CIP family bind and inhibit
    the active CDK-cyclin complex.

http//www.chemsoc.org/exemplarchem/entries/2001/a
rmour/howstrt.htm
107
Internal and external cues help regulate the cell
cycle Internal Signals Messages from the
Kinetochores the APC A gatekeeper at the M phase
checkpoint delays anaphase. Regulators from
kinetochores insures all the chromosomes are
properly attached to the spindle at the metaphase
plate and the anaphase-promoting complex (APC) is
in an inactive state. When all are attached, the
APC then becomes active and indirectly triggers
both the breakdown of cyclin and the inactivation
of proteins holding the sister chromatids
together.
Degradation of key regulator proteins such as the
anaphase inhibitors PDS1 and CUT2, and the
mitosis initiator cyclin B, drives the cell cycle
forward.
108
(No Transcript)
109
Molecular control of the cell cycle at the G2
checkpoint. The Cdk-cyclin complex called MPF,
which acts at the G2 checkpoint to trigger
mitosis. The "maturation-promoting factor"
triggers the cells passage past the G2
checkpoint into M phase Cyclins accumulate during
G2 associate with Cdk molecules, the resulting
MPF complex initiates mitosis. Later in the M
phase, MPF helps switch itself off by initiating
a process that leads to the destruction of its
cyclin by a protein breakdown mechanism
110
Ubiquitin is part of the pathway for the
degradation of proteins
111
Ubiquitin is part of the pathway for the
degradation of proteins
112
External Signals Growth Factors One example of
a growth factor is platelet-derived growth factor
(PDGF), which is made by blood cells called
platelets. The binding of PDGF molecules to
these receptors triggers a signal-transduction
pathway that leads to stimulation of cell
division. The proliferation of fibroblasts helps
heal the wounds.
113
Density-dependent inhibition of cell division.
Most animal cells also exhibit anchorage
dependence Cancer cells exhibit neither
density-dependent inhibition nor anchorage
dependence
114
Cancer cells have escaped from cell cycle
controls Cancer cells do not respond normally to
the bodys control mechanisms. They divide
excessively and invade other tissues. If
unchecked, they can kill the organism.
The growth and metastasis of a malignant breast
tumor. What is a benign tumor? A malignant
tumor? metastasis
Breast cancer animation
115
P53 is considered to be a "Guardian of the
Genome 1. Growth arrest p21, Gadd45, and
14-3-3s. 2. DNA repair p53R2. 3. Apoptosis
Bax, Apaf-1, PUMA and NoxA.
116
P53 re-enforces the G2 checkpoint. This serves
as a tumor suppressor protein.
In the cell, p53 protein binds DNA, which in turn
stimulates another gene to produce a protein
called p21 that interacts with a cell
division-stimulating protein (cdk2). When p21 is
complexed with cdk2 the cell cannot pass through
to the next stage of cell division. Mutant p53
can no longer bind DNA in an effective way, and
as a consequence the p21 protein is not made
available to act as the 'stop signal' for cell
division. Thus cells divide uncontrollably, and
form tumors.
117
http//highered.mcgraw-hill.com/sites/007337797x/s
tudent_view0/chapter9/animation_quiz_-_how_tumor_s
uppressor_genes_block_cell_division.html
118
  • Explain the following diagram

119
(No Transcript)
120
Mitosis vs. Meiosis
121
Meiosis
122
  • Somatic Cells
  • body cells
  • Ex. ___________
  • Made by mitosis
  • Gametes
  • reproductive cells
  • Ex. ________

123
  • Diploid
  • Having 2 copies of each chromosome (2n), one from
    each parent
  • Somatic cells are diploid
  • Human diploid number is _____
  • What are the cells in your body that are diploid?
  • Are gametes diploid? Why or why not?
  • How many chromosomes does a sperm and egg have?
  • Haploid
  • Having only 1 copy of each chromosome (n)
  • Gamete cells are haploid
  • Human haploid number is _____
  • What are the cells in your body that are haploid?

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Copy and fill in the chart below.
Organism Diploid (in somatic cells) Haploid (in gametes)
Cat 19
Rose 12
Goat 30
Rice 24
Dog 39
Chimpanzee 48
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  • Homologous pair
  • A pair of chromosomes, 1 from mom and 1 from dad
  • Carry the same genes (ex. eye color gene)
  • But may contain different information (ex. brown
    eyes and blue eyes)

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Mitosis How our bodies make diploid somatic
cells It happens ________________ Meiosis The
special process of making haploid gametes It
happens in the ______________ ______________ Do
you do mitosis? Do you do meiosis?
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Meiosis Video 1
Mitosis vs. Meiosis Video
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Meiosis
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Homologous Chromosomes are Homies
  • They are always the same SIZE
  • They always have the same type of INFO, but they
    are not identical

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Whiteboard Games
  1. All members help to find the answer
  2. There will be a seat number who will write and a
    seat number who will present

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Game 1 Whose my Homie?
Seat 2Writes
Seat 3--Presents
1 2
3
4 5
6
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Activity
  • Make 1 set of homologous pairs of chromosomes2
    chromosomes
  • Put letters on the chromosomes
  • Demonstrate crossing over
  • Tips Use whiteboard and move beads

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Game 2 Crossing Over
  • On page 90 all members need to draw crossing over
    between homologous chromosomes IN COLOR
  • Book pg 276
  • Drawing 12 homologous chromosomes with letters
  • Drawing 2Crossing over (twisty style)
  • Drawing 3Final chromosomes

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On the bottom of page 90 write
  • Crossing over occurs between homologous
    chromosomes
  • This only occurs in MEIOSIS
  • Crossing over occurs during prophase 1 and leads
    to different sperm and egg

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Dispatch pg 93
  • Crossing over is when________________
  • Crossing over occurs during____phase of meiosis

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Mendels 2 Laws
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Independent Assortment
  • http//www.sumanasinc.com/webcontent/animations/co
    ntent/independentassortment.html

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On pg 91 write
  • Mendels Law of Independent Assortment
    homologous chromosomes line up in different
    combinations during Metaphase I of Meiosis

Draw 2 different alignments
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Game 3 2 alignments for these 2 homies
E
e
  • j J

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Mendels Law 2 pg 92
  • Mendels Law of Segregation allele pairs
    separate during gamete formation and end up in
    different gametes (sperm and egg)

Draw 4 sperm that are segregated
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Game 4 Segregation or Not?
Seat 4Writes
Seat 1--Presents
1 2
3 4
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Who won?
  • Clean up beads, colored pencils, marker and
    whiteboard
  • Get ready for exit quiz

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Exit Quiz
  1. Draw a sperm cell that is segregated
  2. Draw 2 alignments for homologous chromosomes in
    metaphase 1

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Exit Quiz
  1. Explain how the cell cycle is regulated
  2. How does cancer occur?
  3. Give 5 differences between mitosis and meiosis

147
Chapter 12 The Cell Cycle
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Biology is the only subject in which
multiplication is the same thing as division
2007-2008
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Why do cells divide?
  • For reproduction
  • asexual reproduction
  • one-celled organisms
  • For growth
  • from fertilized egg to multi-celled organism
  • For repair renewal
  • replace cells that die from normal wear tear or
    from injury

amoeba
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Importance of Cell Division
  • 1. Growth and Development
  • 2. Asexual Reproduction 3. Tissue Renewal

Zygote Embryo Fetus Adult 1 Cell
100 cells millions cells 100 trillion cells
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DNA organization in Prokaryotes
  • Nucleoid region
  • Bacterial Chromosome
  • Single (1) circular DNA
  • Small
  • (e.g. E. coli is 4.6X106 bp, 1/100th human
    chromosome)
  • Plasmids extra chromosomal DNA

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Bacterial Fission
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The Cell Cycle
  • Interphase (90 of cycle)
  • G1 phase growth
  • S phase synthesis of DNA
  • G2 phase preparation for cell division
  • Mitotic phase
  • Mitosis nuclear division
  • Cytokinesis cytoplasm division

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Parts of Cell Cycle
  • Interphase
  • G1
  • S phase
  • G2
  • M phase
  • Mitosis (Division of nucleus)
  • Prophase
  • Prometaphase
  • Metaphase
  • Anaphase
  • Telophase
  • Cytokinesis (Division of cytoplasm)

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Cell Division Key Roles
  • Genome cells genetic information
  • Somatic (body cells) cells
  • Gametes (reproductive cells) sperm and egg cells
  • Chromosomes condensed DNA molecules
  • Diploid (2n) 2 sets of chromosomes
  • Haploid (1n) 1 set of chromosomes
  • Chromatin DNA-protein complex
  • Chromatids replicated strands of a chromosome
  • Centromere narrowing waist of sister
    chromatids
  • Mitosis nuclear division
  • Cytokinesis cytoplasm division
  • Meiosis gamete cell division

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Chromosome Organization
  • When cells divide, daughter cells must each
    receive complete copy of DNA
  • Each cell has about 2 meters of DNA in the
    nucleus thin threads called chromatin
  • Before division, condenses to form chromosomes
  • DNA also replicates before cell division to
    produce paired chromatids

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157
double-strandedmitotic humanchromosomes
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Normal Karyotype (Fig 18.1)
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159
Mitosis
  • Prophase
  • Prometaphase
  • Metaphase
  • Anaphase
  • Telophase

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Prophase
  • Chromatin condenses
  • visible chromosomes
  • chromatids
  • Centrioles move to opposite poles of cell
  • animal cell
  • Protein fibers cross cell to form mitotic spindle
  • microtubules
  • Nucleolus disappears
  • Nuclear membrane breaks down

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Prometaphase
  • spindle fibers attach to centromeres
  • creating kinetochores
  • microtubules attach at kinetochores
  • connect centromeres to centrioles
  • chromosomes begin moving

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Metaphase
  • Centrosomes at opposite poles
  • Centromeres are aligned
  • Kinetochores of sister chromatids attached to
    microtubules (spindle)

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Anaphase
  • Paired centromeres separate sister chromatids
    liberated
  • Chromosomes move to opposite poles
  • Each pole now has a complete set of chromosomes

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Separation of chromatids
  • In anaphase, proteins holding together sister
    chromatids are inactivated
  • separate to become individual chromosomes

1 chromosome 2 chromatids
2 chromosomes
single-stranded
double-stranded
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Telophase
  • Daughter nuclei form
  • Nuclear envelopes arise
  • Chromatin becomes less coiled
  • Two new nuclei complete mitosis
  • Cytokinesis begins
  • cell division

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Mitosis in whitefish blastula
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Mitosis in plant cell
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