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Cell Cycle…

• Does your cell cycle look something like this?

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Lesson Lesson #1.3a - #1.3a - MitosisMitosis

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Identical Daughter Identical Daughter CellsCells

Parent CellParent Cell

Two Two identical identical daughter daughter

cellscells

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ChromosomChromosomeses

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Chromosomes in Dividing Chromosomes in Dividing CellsCells

Duplicated chromosomes are called sister chromatids & are held together by the centromere

Called Sister Called Sister ChromatidsChromatids

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KaryotypeKaryotypeA A picturepicture of the of the

chromosomes chromosomes from a from a humanhuman cell cell arranged in arranged in pairspairs by by sizesize

First First 2222 pairs are pairs are called called autosomesautosomes

Last Last pairpair are the are the sex chromosomessex chromosomes

XXXX female or female or XYXY malemale

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Boy or Girl?Boy or Girl?

Y - Y - ChromosomeChromosome

X - X - ChromosomeChromosome

The Y Chromosome The Y Chromosome DecidesDecides

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Cell Cell ReproductionReproduction

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Types of Cell Types of Cell ReproductionReproductionAsexualAsexual reproduction reproduction involves involves a a

single cellsingle cell dividing to make dividing to make 22 new, new, identical cellsidentical cells, these are , these are called called daughter cellsdaughter cellsMitosis & binary fission Mitosis & binary fission are examples of are examples of

asexual reproductionasexual reproduction

SexualSexual reproduction reproduction involves two involves two cells (cells (egg & spermegg & sperm) joining to ) joining to make a make a new cell (zygote)new cell (zygote) that is that is NOTNOT identical to the original cells identical to the original cellsMeiosisMeiosis is an exampleis an example

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Cell CycleCell Cycle

DaughteDaughter Cellsr Cells

DNA DNA CopiedCopied

Cells Cells MaturMatur

ee

Cells prepare Cells prepare for Divisionfor Division

Cell Divides into Cell Divides into Identical cellsIdentical cells

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What’s Happening in What’s Happening in Interphase?Interphase?

What the cell looks likeWhat the cell looks like

Animal Cell

What’s occurring

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MitosisMitosis

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MitosisMitosisDivision of the Division of the

nucleusnucleusOnly occurs in Only occurs in

eukaryoteseukaryotesProduces Produces

somaticsomatic cellscells (ALL but sex (ALL but sex cells)cells)

Has Has four four stagesstagesDoesn’t occur in Doesn’t occur in

some cells such some cells such as as brain cellsbrain cells

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Four Mitotic StagesFour Mitotic Stages

PProrophasephaseMMetaetaphasephaseAAnanaphasephaseTTeloelophasephase

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Early ProphaseEarly ProphaseChromatin Chromatin in nucleus continues in nucleus continues

condensing condensing Mitotic Mitotic spindlespindle forms from forms from

centriolescentriolesMicrotubulesMicrotubules make up the spindle fibres make up the spindle fibres

ChromosomesChromosomes

NucleolusNucleolus CytoplasmCytoplasm

Nuclear MembraneNuclear Membrane

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Late ProphaseLate ProphaseNuclear membrane & Nuclear membrane & nucleolus nucleolus

are are broken downbroken downChromosomesChromosomes continue continue

condensing & are condensing & are clearly visibleclearly visibleSpindle fibers Spindle fibers attach to the attach to the

centromerecentromere o of each chromosomef each chromosomeSpindleSpindle beginbegin to move to the to move to the

opposite endsopposite ends of the cell, of the cell, stretchingstretching out the cell out the cell

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Late ProphaseLate Prophase

Nucleus & Nucleolus have disintegratedNucleus & Nucleolus have disintegrated

ChromosomeChromosomes s

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Review of ProphaseReview of Prophase

What the cell What the cell looks likelooks like

What’s happeningWhat’s happeningCentromere

s

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MetaphaseMetaphaseChromosomes, attached to the Chromosomes, attached to the

centromeres centromeres and move to the and move to the centercenter of the cell of the cell

Chromosomes are now Chromosomes are now lined up in lined up in the middlethe middle

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MetaphaseMetaphase

ChromosoChromosomes lined mes lined up in the up in the middlemiddle

Spindle Spindle FibersFibers

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MetaphaseMetaphase

ChromosomesChromosomes

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Review of MetaphaseReview of Metaphase

What the cell What the cell looks likelooks like

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AnaphaseAnaphaseOccurs Occurs rapidlyrapidlySister Sister

chromatidschromatids are are pulled pulled apart apart to to opposite opposite polespoles of the cell by of the cell by spindle fibersspindle fibers

Cell Cell elongateselongates (gets wider)(gets wider)

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AnaphaseAnaphase

Sister Sister ChromatidChromatid

s being s being separatedseparated

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Anaphase ReviewAnaphase Review

What What the cell the cell looks looks likelike

What’s What’s occurrioccurri

ngng

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TelophaseTelophaseSister chromatids Sister chromatids are now are now at at oppositeopposite poles poles

Spindle Spindle disassemblesdisassemblesNuclear envelopeNuclear envelope formsforms around around each set each set of sister chromatidsof sister chromatids

NucleolusNucleolus reappearsreappearsCYTOKINESISCYTOKINESIS begins at the end begins at the end of this stageof this stage

Chromosomes reappear as Chromosomes reappear as chromatinchromatin

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Comparison of Anaphase & Comparison of Anaphase & TelophaseTelophase

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“Activity: Mitosis Practice” worksheet

(front side only)

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CytokinesisCytokinesisMeans division of the Means division of the

cytoplasmcytoplasmDivisionDivision of cell into of cell into twotwo, ,

identicalidentical halves called halves called daughter cellsdaughter cells

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Mitotic StagesMitotic Stages

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Daughter Cells of MitosisDaughter Cells of MitosisHave the Have the samesame number of number of

chromosomeschromosomes as each other as each other and as the and as the parent cell parent cell from from which they were formedwhich they were formed

IdenticalIdentical to each other, but to each other, but smallersmaller than parent cell than parent cell

Must Must grow in size grow in size to become to become maturemature cells cells (G(G11 of Interphase) of Interphase)

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Identical Daughter CellsIdentical Daughter Cells

Chromosome number the Chromosome number the samesame

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RevieReview of w of

MitosiMitosiss

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InterphaseInterphase

ProphaseProphase

MetaphaseMetaphaseAnaphaseAnaphase

TelophaseTelophase

Name the Mitotic Stages:Name the Mitotic Stages:start

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Eukaryotic Cell DivisionEukaryotic Cell Division

Used for Used for growth and growth and repairrepair

Produce Produce twotwo new cells new cells identicalidentical to the original to the original cellcell

Cells are Cells are diploid (2n)diploid (2n)Chromosomes Chromosomes

during Metaphase during Metaphase of mitosisof mitosis

ProphaProphasese

MetaphaseMetaphase AnaphaseAnaphaseTelophaseTelophaseCytokinesisCytokinesis

REMEMBER… PMAT + Cytokinesis = Mitotic Phase

P M A T

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Mitosis AnimationMitosis AnimationName each stage as you see it Name each stage as you see it

occur?occur?

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Mitosis in Onion Root Mitosis in Onion Root TipsTips

Do you see any stages of mitosis?Do you see any stages of mitosis?

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Test Yourself Test Yourself over Mitosisover Mitosis

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Name the Stages of Name the Stages of Mitosis:Mitosis:

Interphase

prophase

ProphaseProphase

Metaphase

Anaphase

Anaphase

Telophase,

cytokinesis

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Identify the StagesIdentify the Stages

Prophase Prophase

ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase

AnaphaseAnaphase TelophaseTelophase TelophaseTelophase

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?? ?? ??

?? ?? ??

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1. “Activity: Mitosis Practice” worksheet (back side)

2. CELL CYCLE worksheet and questions

3. Mitosis Worksheet #1-24 & #1-104. Mitosis QUIZ practice