Transcript Teacher quality grant

Biology Partnership
(A Teacher Quality Grant)
Cell Cycle
Mitosis & Cell Cycle Regulation
Nancy Dow
Jill Hansen
Tammy Stundon
November 3, 2012
Gulf Coast State College
Panhandle Area Educational Consortium
5230 West Highway 98
753 West Boulevard
Panama City, Florida 32401
Chipley, Florida 32428
850-769-1551
877-873-7232
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www.gulfcoast.edu
Pre-test
Q and A board
What is Mitosis?
What is Meiosis?
When do they happen?
What is alike and what is different about them?
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Bell Ringer
Mitosis Rap
"Mitosis" - Justin Bieber Baby remix!
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Florida Next Generation
Sunshine State Standards
BENCHMARK
• SC.912.L.16.14 Describe the cell cycle, including the process of
mitosis. Explain the role of mitosis in the formation of new cells
and its importance in maintaining chromosome number during
asexual reproduction. Moderate complexity
Clarifications
• Students will describe specific events occurring in each of the
stages of the cell cycle and/or phases of mitosis.
• Students will explain how mitosis forms new cells and its role in
maintaining chromosome number during asexual reproduction.
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Content Limits
• Items may address the presence and location of
centrioles but may not require knowledge of the
function of centrioles.
• Items addressing mitosis or meiosis are limited to
identification of phases, structures, and major
events of each phase.
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KEY CONCEPT
Cells have distinct phases of growth, reproduction,
and normal functions.
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lung cancer cell undergoing cell division
• Activate prior Knowledge: To get students
thinking about doubling and division, have them think
about baking cookies.
•Ask, if you want two batches of cookies, not just one,
what do you need to do to the recipe? •Double it.
•Discuss that doubling a recipe means doubling all of the
ingredients in the original recipe. Have students apply this
idea to cell division.
•Ask, for cells to be functional after division, what needs to
be present?
•Complete set of DNA, organelles,
cytoplasm, cell membrane, cell wall if a
plant.
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Preview Vocabulary:
• Cycle=Latin root Circlus= circle( repeating series of
events)
• Phase =Greek origin phasis= appearance (Remind
students of the phases of the moon. Each phase of
mitosis has a distinctive appearance.)
• Stage=Latin word status= stand (students can think in
terms of stagecoaches and stopping points, or stands,
along a journey. A cell must move through the stages
in the cell cycle to reach the point where it can
successfully divide.)
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Recall
• Cells have 3 main jobs
– make energy
• need food + O2
• cellular respiration & photosynthesis
• need to remove wastes
Our organelles
do all those
jobs!
– make proteins
• need instructions from DNA
• need to chain together amino acids & “finish”
& “ship” the protein
– make more cells
• need to copy DNA & divide it up to daughter cells
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The cell cycle has four main stages.
• The cell cycle is a regular pattern of growth,
DNA replication, and cell division.
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• The main stages of the cell cycle are gap 1,
synthesis, gap 2, and mitosis.
– Gap 1 (G1): cell growth and
normal functions
– DNA synthesis (S): copies
DNA
– Gap 2 (G2): additional
growth
– Mitosis (M): includes
division of the cell nucleus
(mitosis) and division of the
cell cytoplasm (cytokinesis)
• Mitosis occurs only if the cell is large enough and the DNA
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undamaged.
DNA REPLICATION DURING ‘S’ PHASE OF CYCLE
Adenine
Cytosine
Guanine
Thymine
1 UNWINDING
The coiled, doublestranded DNA
molecule unwinds
and separates into Free nucleotide
two strands.
2 REBUILDING
Each of the single
strands becomes a
double strand again as
an enzyme connects
the appropriate
complementary base
to the exposed base.
The free nucleotides
come from your food.
1
2
Complementary
nucleotide bases
attached
ERRORS
(MUTATIONS)
CAN OCCUR
WITH BASES
DURING
DNA
Replication
____________
Why do Cells need to Divide?
• Single cell organisms
– Asexual reproduction
• Multicellular organisms
– Growth
– Development
– Repair
Cells divide at different rates.
• The rate of cell division varies with the need for
those types of cells.
• ~100 Trillion cells in the human body
• ~100 Billion of them replicate each day
• Some cells are unlikely to divide (G0).
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Cell size is limited.
• Volume increases faster than surface area.
Larger cells would either starve to death or be
poisoned from the buildup of waste products.
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WHY ARE CELLS SMALL ??
BECAUSE OF SURFACE AREA- TO- VOLUME RATIO
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• Surface area must allow for
adequate exchange of
materials.
– Cell growth is coordinated with
division.
– Cells that must be large have
unique shapes.
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KEY CONCEPT
Cells divide during mitosis and cytokinesis.
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Chromosomes condense at the start
of mitosis.
• DNA wraps around proteins (histones) that
condense it.
DNA double
helix
DNA and
histones
Chromatin
Supercoiled
DNA
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Recall
chromatid
telomere
centromere
•DNA plus proteins is called
chromatin.
• One half of a duplicated
chromosome is a chromatid.
• Sister chromatids are held
together at the centromere.
• Telomeres protect DNA and do
not include genes.
telomere
Condensed, duplicated chromosome
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HOMOLOGUES AND SISTER CHROMATIDS
Homologues are the maternal and paternal copies of a chromosome. A sister
chromatid is a chromosome and its identical duplicated version held together
at a centromere.
Homologues
Homologues
Replication
(S Phase)
Centromere
Maternal
chromosome
Paternal
chromosome
Sister
chromatids
Sister
chromatids
A downside to cell division:
TELOMERES
Animal cell
Every time a cell divides, the telomere gets shorter.
After a critical number of cell divisions, functional
DNA is lost, which means almost certain death for
the cell.
Nucleus
Chromosome
Functional DNA
TELOMERE
A protective cap at the
end of each chromosome
TELOMERES HAVE BEEN COMPARED TO THE ENDS OF A SHOELACE.
AFTER A LOT OF WEAR, THE END OF THE SHOELACE GETS FRAYED.
TELOMERES
TELOMERE A protective cap at the
Functional DNA end of each chromosome
Cell division
Cell division
Cell division

Cell death
NOW THE CELL DOES
NOT REPLACE ITSELF
WHICH CAUSES THE AGING
PROCESS TO OCCUR
At birth, telomeres in most human cells are long
enough to support about 50 cell divisions!
Telomere Studies May Explain
Rare Aging Disease in Children
• Study of children with rare case of
genetic mutation that causes drastic
early aging and death is now being
linked to short or missing Telomeres by top scientists.
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PROGERIA: BORN WITH SHORTER
TELOMERES---THESE ARE
HIGHLIGHTED IN YELLOW IN PIC.
THE CHILD DIES OF OLD AGE.
Mitosis and cytokinesis produce two
genetically identical daughter cells.
Parent cell
• Interphase
prepares the cell
to divide.
• During
Interphase, the
DNA is
duplicated.
centrioles
spindle fibers
centrosome
nucleus with
DNA
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• Mitosis divides the cell’s nucleus in four phases.
– During prophase, chromosomes condense and
nuclear membrane breaks down.
– centrioles ‘move’ to the poles and spindle fibers form
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• Mitosis divides the cell’s nucleus in four phases.
– During metaphase, chromosomes line up in the
middle of the cell.
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• Mitosis divides the cell’s nucleus in four phases.
– During anaphase, sister chromatids separate to
opposite sides of the cell.
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• Mitosis divides the cell’s nucleus in four phases.
– During telophase, the new nuclei form, spindle fibers
break down and chromosomes begin to uncoil.
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• Cytokinesis differs in animal and plant cells.
– In animal cells, the
membrane pinches
closed.
– In plant cells, a cell
plate forms.
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Mitosis in plant cells
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• Mitosis Animation
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Mitosis in whitefish blastula
Mitosis in Onion root tip
Cell Cycle Lab
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See you in the Computer
Lab
Let’s go to the Computer Lab
• Mitosis Virtual Lab – Onion Tip
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Mitosis Dance
• Jill will lead us in this dance
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Follow up
•
•
•
•
•
•
•
Mitosis Dance
Mitosis animation
another mitosis animation
Animating Mitosis (flipbook)
Mitosis: Read Retrieve Connect & Use
Mitosis Puzzle
Cell Cycle Project
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Florida Next Generation
Sunshine State Standards
Benchmark
• SC.912.L.16.8 Explain the relationship between mutation, cell cycle,
and uncontrolled cell growth potentially resulting in cancer.
(cognitive complexity: Moderate)
Clarifications
• Students will explain how cancer (uncontrolled cell growth) may
result from mutations that affect the proteins that regulate the cell
cycle.
Content Limits
• Items will focus on the relationship between mutations and
uncontrolled cell growth, rather than a specific mutation that may
result in uncontrolled cell growth.
• Items referring to mutation will focus on the general concepts of
uncontrolled cell growth and not require specific knowledge of
cancers or diseases resulting from that growth.
• Items will not assess the specific proteins associated with regulating
the cell cycle.
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KEY CONCEPT
Cell cycle regulation is necessary for healthy
growth.
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Internal and external factors regulate cell division.
• External factors include physical and chemical
signals.
• Growth factors are proteins that stimulate cell
division.
– Most mammal cells form a single layer in a culture
dish and stop dividing once they touch other cells.
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• Two of the most important internal factors are
kinases and cyclins.
• Kinases- change the activity of other
molecules
• Cyclins- rapidly made and destroyed at
different points in the cell cycle
• External factors trigger internal factors, which affect the
cell cycle.
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• Apoptosis is programmed cell death.
– a normal feature of healthy organisms
– caused by a cell’s production of self-destructive
enzymes
webbed fingers
– occurs in
development
of infants
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Cell division is uncontrolled in cancer.
• Cancer cells form disorganized clumps called
tumors.
– Benign tumors remain clustered and can be removed.
– Malignant tumors metastasize, or break away, and can
form more tumors.
normal cell
cancer cell
bloodstream
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• Cancer cells do not carry out necessary
functions.
• Cancer cells come from normal cells with damage to
genes involved in cell-cycle regulation.
How cancer grows and spreads interactive
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• Carcinogens are substances known to promote
cancer.
• Standard cancer treatments typically kill both cancerous
and healthy cells.
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Carcinogens
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Prevention
• 1. don't smoke
• 30% of all cancer
• 2. don't sunbath/booths
• melanoma
• 3. avoid alcohol
• mouth, liver, larynx cancers
• 4. avoid radiation
• x rays
• 5. get tested
• catch it early on
• 6. Diet
• increase by 55% with obesity
• high fiber, Vit. A and C, broccoli, cabbage
• HeLa Cell Activity
• Khan Academy- cancer
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Follow up
• Q&A
• Post Test
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