Standard BiologyStandard BiologyChapter 22Chapter 22

Cellular Cellular ReproductionReproductionSection 22:1 MitosisSection 22:1 Mitosis

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MitosisMitosis

One cell divides One cell divides and divides to and divides to form 3 trillion form 3 trillion cells (you)cells (you)

Process of cell Process of cell reproduction by reproduction by which 2 new which 2 new identical cells identical cells are formed from are formed from one parent cellone parent cell

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MitosisMitosis

Needed for Needed for growth, repair, growth, repair, and replacement and replacement of body partsof body parts

Growth: new Growth: new musclemuscle

Repair: broken Repair: broken bone need new bone need new bone cellsbone cells

Replacement: new Replacement: new blood cells when blood cells when have loss of bloodhave loss of blood

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MitosisMitosis

All body cells are All body cells are formed by formed by mitosis (body mitosis (body cells are all cells cells are all cells that are not sex that are not sex cells)cells)

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Different Cells Have Different Cells Have Different Life SpanDifferent Life Span

Cell TypeCell Type

Brain CellBrain Cell

Red Blood CellRed Blood Cell

PlateletsPlatelets

Stomach LiningStomach Lining

Liver CellsLiver Cells

Intestine LiningIntestine Lining

SkinSkin

Life SpanLife Span

30-50 years30-50 years

120 days120 days

10 days10 days

2 days2 days

200 days200 days

3 days3 days

20 days20 days

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MitosisMitosis

Mitosis Mitosis continues your continues your entire lifeentire life

Cells go through Cells go through mitosis at mitosis at different rates, different rates, some are slow some are slow and some are and some are fastfast

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Cell CycleCell Cycle Most of the time cells Most of the time cells

are not dividing, they are not dividing, they are just growing and are just growing and doing their jobdoing their job

Interphase: time Interphase: time between mitosis between mitosis when cells grow, do when cells grow, do their job and get their job and get ready for mitosis by:ready for mitosis by:

Doubling Doubling chromosomes get chromosomes get sister chromatidssister chromatids

Making more cell Making more cell parts (mitochondria…)parts (mitochondria…)

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Steps of Mitosis Steps of Mitosis

ProphaseProphase Sister chromatids thicken so Sister chromatids thicken so

can be seencan be seen Nuclear membrane disappearsNuclear membrane disappears Centrioles (animals only) move Centrioles (animals only) move

away from each otheraway from each other Spindle fibers form between Spindle fibers form between

centriolescentrioles

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Prophase Prophase

a. Chromosome (two sister chromatids)

b. Centriole

c. Spindle fiber

d. Nuclear membrane (disintegrating)

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Prophase Prophase

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Steps of Mitosis Steps of Mitosis

MetaphaseMetaphase Sister chromatids are hooked to Sister chromatids are hooked to

spindle fiberspindle fiber Sister chromatids are in center Sister chromatids are in center

of cellof cell

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MetaphaseMetaphase

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MetaphaseMetaphase

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Steps of Mitosis Steps of Mitosis

AnaphaseAnaphase Sister chromatids are pulled Sister chromatids are pulled

apartapart

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AnaphaseAnaphase

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AnaphaseAnaphase

PLANT

ANIMAL

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Steps of Mitosis Steps of Mitosis

TelophaseTelophase Each chromatid forms a nucleusEach chromatid forms a nucleus Nuclear membrane forms around Nuclear membrane forms around

the 2 new nucleithe 2 new nuclei Spindle fibers disappearSpindle fibers disappear Chromatids thin and can’t be seenChromatids thin and can’t be seen Cell cytoplasm usually divides Cell cytoplasm usually divides

(cytokinesis)(cytokinesis)

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TelophaseTelophase

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TelophaseTelophase

After Telophase After Telophase the 2 new cells the 2 new cells are in interphaseare in interphase

Cytokinesis is Cytokinesis is the division of the division of the cell contents the cell contents forming two new forming two new cellscells

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Results of Mitosis Results of Mitosis

Results of Results of mitosis: get 2 mitosis: get 2 new cells that new cells that are genetically are genetically identical (same identical (same chromosome) but chromosome) but smaller in sizesmaller in size

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Differences between mitosis Differences between mitosis in plants and animalsin plants and animals

1. Plants don’t 1. Plants don’t have centrioles, have centrioles, animals cells animals cells do; both have do; both have spindle fibersspindle fibers

Centrioles

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Differences between mitosis Differences between mitosis in plants and animalsin plants and animals

2. Plants have 2. Plants have cell wall so cell wall so must add more must add more cell wall cell wall between new between new cells not just cells not just pinch in pinch in cytoplasm to cytoplasm to divide itdivide it

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Standard BiologyStandard BiologyChapter 22Chapter 22

Cellular Cellular ReproductionReproductionSection 22:2 Meiosis Section 22:2 Meiosis

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MeiosisMeiosis Sex cells (eggs and Sex cells (eggs and

sperm) are sperm) are produced by a produced by a process different process different from mitosisfrom mitosis

Meiosis: cell divides Meiosis: cell divides twice to form 4 new twice to form 4 new cells each with ½ cells each with ½ the number of the number of chromosomeschromosomes

Start with one body Start with one body cell end with 4 sex cell end with 4 sex cellscells

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MeiosisMeiosis

Interphase happens just like Interphase happens just like mitosis, chromosomes are mitosis, chromosomes are doubleddoubled

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Steps of Meiosis:Steps of Meiosis:Meiosis IMeiosis I

Prophase IProphase I Sister chromatids shorten and thickenSister chromatids shorten and thicken Nuclear membrane disappearsNuclear membrane disappears Centrioles move to opposite ends of cellCentrioles move to opposite ends of cell Spindle fibers formSpindle fibers form Two pair of sister chromatids Two pair of sister chromatids

(matching chromosomes) come (matching chromosomes) come together; get tetrads; together; get tetrads; exchange genetic exchange genetic materialmaterial

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Steps of Meiosis:Steps of Meiosis:Meiosis IMeiosis I

ProphasProphase Ie I

HomologoHomologous us ChromosoChromosomesmes

(tetrads)(tetrads)

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Steps of Meiosis:Steps of Meiosis:Meiosis IMeiosis I

Metaphase IMetaphase I Tetrads in center of cellTetrads in center of cell Spindle fibers attached to Spindle fibers attached to

chromosomeschromosomes

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Steps of Meiosis:Steps of Meiosis:Meiosis IMeiosis I

MetaphasMetaphase Ie I

TetraTetradsds

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Steps of Meiosis:Steps of Meiosis:Meiosis IMeiosis I

Anaphase IAnaphase I A pair of sister chromatids gets A pair of sister chromatids gets

pulled away from the other pair pulled away from the other pair of sister chromatidsof sister chromatids

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Steps of Meiosis:Steps of Meiosis:Meiosis IMeiosis I

Telophase ITelophase I Cell dividesCell divides Nuclear membrane DOES NOT Nuclear membrane DOES NOT

REFORMREFORM

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Steps of Meiosis:Steps of Meiosis:Meiosis IIMeiosis II

Prophase II and Metaphase IIProphase II and Metaphase II Spindle fibers attach to sister Spindle fibers attach to sister

chromatidschromatids Sister chromatids are in middle Sister chromatids are in middle

of cellof cell

Prophase II Metaphase II

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Steps of Meiosis:Steps of Meiosis:Meiosis IIMeiosis II

Anaphase II and Telophase IIAnaphase II and Telophase II Sister chromatids are pulled Sister chromatids are pulled

apartapart Nuclear membrane reformsNuclear membrane reforms

Anaphase II Telophase II

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Result of MeiosisResult of Meiosis

Results of Results of Meiosis: end with Meiosis: end with 4 sex cells that 4 sex cells that have ½ of the have ½ of the chromosomes as chromosomes as parent cellparent cell

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Sperm, Egg, and Sperm, Egg, and FertilizationFertilization

Comparison of Sperm and Comparison of Sperm and EggEgg

How AlikeHow Alike

1.1. sex cellssex cells

2.2. formed by meiosisformed by meiosis

3.3. ½ number of ½ number of chromosomeschromosomes

4.4. humans develop at humans develop at pubertypuberty

How DifferentHow Different

1.1. egg larger than spermegg larger than sperm

2.2. sperm has tail, can sperm has tail, can movemove

3.3. sperm form in male sperm form in male testestestes

4.4. eggs form in female eggs form in female ovaryovary

5.5. only get 1 egg in only get 1 egg in meiosismeiosis

6.6. get 4 sperm in meiosisget 4 sperm in meiosis

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Sperm, Egg, and Sperm, Egg, and FertilizationFertilization

Formation of Polar BodiesFormation of Polar Bodies Happens in meiosis to produce Happens in meiosis to produce

eggseggs Cell division is not equal, most of Cell division is not equal, most of

cytoplasm goes to one cellcytoplasm goes to one cell Polar body is the cell formed with Polar body is the cell formed with

little cytoplasmlittle cytoplasm Polar bodies do not form eggs, Polar bodies do not form eggs,

they diethey die

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Sperm, Egg, and Sperm, Egg, and FertilizationFertilization

Formation of Polar BodiesFormation of Polar Bodies

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Sperm, Egg, and Sperm, Egg, and FertilizationFertilization

FertilizationFertilization Joining of sperm and eggJoining of sperm and egg Chromosomes come together and Chromosomes come together and

pair up forming a new organism pair up forming a new organism with the correct number of with the correct number of chromosomeschromosomes

New organism has ½ New organism has ½ chromosomes form mother and ½ chromosomes form mother and ½ chromosomes from fatherchromosomes from father

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Sperm, Egg, and Sperm, Egg, and FertilizationFertilization

Standard BiologyStandard BiologyChapter 22Chapter 22

Cellular Cellular ReproductionReproduction

Section 22:3 Changes in the Section 22:3 Changes in the Rate of MitosisRate of Mitosis

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Changes that Occur in the Changes that Occur in the Human Body with AgeHuman Body with AgeBody Body

SystemSystemTraitTrait 20 20

Year Year OldOld

70 70 Year Year OldOld

Skin/NailsSkin/Nails Rate of Rate of fingernail fingernail growthgrowth

1mm/1mm/

weekweek0.6mm0.6mm/week/week

NervousNervous Reaction TimeReaction Time 0.8 0.8 secsec

0.95 0.95 secsec

CirculatoryCirculatory Pumping Pumping action of action of heartheart

3.7 L/ 3.7 L/ minmin

2.9 L/ 2.9 L/ minmin

NervousNervous MemoryMemory 14 of 14 of 24 24 words words recallrecalleded

7 of 24 7 of 24 words words recallerecalledd

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Changes that Occur in the Changes that Occur in the Human Body with AgeHuman Body with AgeBody Body

SystemSystemTraitTrait 20 20

Year Year OldOld

70 70 Year Year OldOld

RespiratoryRespiratory Lung volume Lung volume per breathper breath

5.5 L/ 5.5 L/ inhalatiinhalationon

3.0 L/3.0 L/

inhalatiinhalationon

MuscularMuscular % body fat % body fat (male)(male)

15%15% 30%30%

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AgingAging Becoming olderBecoming older All living things ageAll living things age Loss of hairLoss of hair Wrinkled skinWrinkled skin Bone calcium lossBone calcium loss Cells wear out faster than they are replaced Cells wear out faster than they are replaced

or are not replaced (or are not replaced (mitosis slows downmitosis slows down)) Muscle cells (including heart) are not Muscle cells (including heart) are not

replaced, each cell can get bigger but replaced, each cell can get bigger but no no new cellsnew cells

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AgingAging

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CancerCancer

Healthy cells: Healthy cells: regular rate of regular rate of mitosismitosis

Cancer: too fast Cancer: too fast rate of mitosisrate of mitosis Shape of cell and Shape of cell and

nuclei changenuclei change Abnormal cells Abnormal cells

crowd out normal crowd out normal cellscells

Fig 22-11 p. 478Fig 22-11 p. 478

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Causes of CancerCauses of Cancer

Environmental Environmental factorsfactors

Chemicals: Chemicals: chewing tobacco chewing tobacco (mouth)(mouth)

Smoking tobacco Smoking tobacco (lung)(lung)

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Causes of CancerCauses of Cancer

Environmental Environmental factorsfactors

Radiation: UV Radiation: UV light (skin)light (skin)

Viruses: (warts Viruses: (warts and cervical and cervical cancer)cancer)

DietDiet

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Causes of CancerCauses of Cancer

Genetic FactorsGenetic Factors Runs in a familyRuns in a family Locate the gene Locate the gene

may be able to may be able to prevent the cancerprevent the cancer Many cancers Many cancers

thought to be a thought to be a combination of combination of environmental and environmental and genetic factorsgenetic factors