Lect9F Life and Cell 2011

8/3/2019 Lect9F Life and Cell 2011

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Lecture 9: Life and CellsLecture 9: Life and Cells

Teaching should be such that what is offe redis perceived as a valuable gift and not as a hard duty.

Albert Einstein

LECTURE FLOWLECTURE FLOW

I.I. INTRODUCTIONINTRODUCTION

I.I. CELLSCELLS

Prokaryotes and EukaryotesProkaryotes and Eukaryotes

Animal and Plant CellsAnimal and Plant Cells

III. PLANT CELL STRUCTUREIII. PLANT CELL STRUCTURE

IV. STEM CELLIV. STEM CELL

V. CELL CASEV. CELL CASE

I. INTRODUCTIONI. INTRODUCTIONBiological OrganizationBiological Organization

1.1. Subatomic ParticlesSubatomic Particles

2.2. AtomsAtoms

3.3. Molecules (Small Molecules,Molecules (Small Molecules,Macromolecules & MolecularMacromolecules & MolecularAssemblies)Assemblies)

4.4. OrganelleOrganelle

5.5. CellCell

6.6. TissueTissue

7.7. OrganOrgan

8.8. Organ SystemOrgan System

9.9. OrganismOrganism

10.10. PopulationPopulation

11.11. SpeciesSpecies

12.12. CommunityCommunity

13.13. EcosystemEcosystem

14.14. BiosphereBiospherewww.desktopclass.com/education/fafsc/levels-o...

Subatomic ParticlesSubatomic Particles:: ProtonsProtons,, neutronsneutrons andand electronselectrons are theare themain subatomic particles which reside in a substance.main subatomic particles which reside in a substance.

AtomsAtoms:: Atoms are defined as the smallest unit or the basicAtoms are defined as the smallest unit or the basicbuilding blocks of matter which make up all objects . Atoms are madebuilding blocks of matter which make up all objects . Atoms are made

up of equal number of protons and electronsup of equal number of protons and electrons

Small MoleculesSmall Molecules:: Larger molecules are made up of someLarger molecules are made up of somebuilding blocks and these blocks are attributed as small molecules.building blocks and these blocks are attributed as small molecules.Examples of such molecules are amino acids, fatty acids, glucose,Examples of such molecules are amino acids, fatty acids, glucose,

etc.etc.

MacromoleculesMacromolecules:: Macromolecules are defined as large orMacromolecules are defined as large orgigantic molecules which populate a cell and render the importantgigantic molecules which populate a cell and render the importantfunctions of life. Examples are carbohydrates, lipids, proteins,functions of life. Examples are carbohydrates, lipids, proteins,

nucleic acids, etc.nucleic acids, etc.

Molecular AssembliesMolecular Assemblies:: These assemblies are organized setsThese assemblies are organized setswhich comprise one or more molecular entity (i.e. the microtubule,which comprise one or more molecular entity (i.e. the microtubule,conveyor belts inside the cells, and the cell membrane or plasmaconveyor belts inside the cells, and the cell membrane or plasma

membrane)membrane)


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OrganelleOrganelle:: Organelle means little organs and is a specialized partOrganelle means little organs and is a specialized partof a cell (i.e. the nucleus, endoplasmic reticulum, mitochondria, etc.)of a cell (i.e. the nucleus, endoplasmic reticulum, mitochondria, etc.)

CellCell:: The smallest unit of life (living organisms), and is theThe smallest unit of life (living organisms), and is thestructural and functional units of organisms (i.e. bacteria, amoeba,structural and functional units of organisms (i.e. bacteria, amoeba,

archaebacteriaarchaebacteria, etc, are all single, etc, are all single--celled organisms, and humanscelled organisms, and humans

and many other organisms areand many other organisms are multicellularmulticellular))

TissueTissue:: It is a group of cells with similar or differentIt is a group of cells with similar or differentcharacteristics, and attributed with a particular set of functions in thecharacteristics, and attributed with a particular set of functions in the

body of the livingbody of the living organismnorganismn (i.e.(i.e. meristematicmeristematic and permanentand permanent

tissues in plants).tissues in plants).

OrganOrgan:: It is an organization of different types of tissuesIt is an organization of different types of tissues

Organ SystemOrgan System:: It is a group of organs for performing a broad setIt is a group of organs for performing a broad setof functions, particularly in multiof functions, particularly in multi--cellular organisms.cellular organisms.

OrganismOrganism:: It can be regarded as the complete framework ofIt can be regarded as the complete framework oforgan systems, organs, organelle and all other components whichorgan systems, organs, organelle and all other components which

work in their own specific way in order t o carry out the variouswork in their own specific way in order t o carry out the various

processes of life (i.e. plants, animals, humans, bacterium, etc)processes of life (i.e. plants, animals, humans, bacterium, etc)

PopulationPopulation:: A group of interA group of inter--breeding organisms of the samebreeding organisms of the samespecies inhabiting a defined area is termed as a populationspecies inhabiting a defined area is termed as a population

SpeciesSpecies:: Species is merely a defining term given to a specific kindSpecies is merely a defining term given to a specific kindof organismof organism

CommunityCommunity:: A group of interacting organisms of differentA group of interacting organisms of differentspecies living in a given area is termed as a community.species living in a given area is termed as a community.

EcosystemEcosystem:: An ecosystem is made up of both biotic orAn ecosystem is made up of both biotic or abioticabioticcomponents of the environment such as the c limate, landscape,components of the environment such as the c limate, landscape,

animals and plants; interaction of a group of organisms and theiranimals and plants; interaction of a group of organisms and their

environment, to be precise!environment, to be precise!

BiosphereBiosphere:: It is simply defined as the regions on, below, andIt is simply defined as the regions on, below, andabove the surface, and atmosphere of the Earth where livingabove the surface, and atmosphere of the Earth where living

organisms exist.organisms exist.

QuarkQuark

Quarks are believed to be one of the basicQuarks are believed to be one of the basicbuilding blocks of matter.building blocks of matter.

Quarks were first discovered in experiments done at theQuarks were first discovered in experiments done at theStanford Linear Accelerator CenterStanford Linear Accelerator Center in the late 1960's andin the late 1960's andearly 1970's.early 1970's.

Three families of quarks are known to exist, andThree families of quarks are known to exist, andeach family contains two quarks.each family contains two quarks.I.I. Up and Down quarks, the quarks that join together toUp and Down quarks, the quarks that join together to

formform protonsprotons andand neutronsneutrons..

II.II. Strange and Charm quarks and only exist at highStrange and Charm quarks and only exist at highenergies.energies.

III.III. Top and Bottom quarks and only exist at very highTop and Bottom quarks and only exist at very highenergies. The Top quark was finallyenergies. The Top quark was finally discovereddiscovered in 1995in 1995at theat the Fermi National Accelerator LaboratoryFermi National Accelerator Laboratory..


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II. CELLSII. CELLS

1.1. Basic DescriptionBasic Description

Cells of plants are tiny, measuring on average aboutCells of plants are tiny, measuring on average about1010--100100 mmm across (m across (11 cm =cm = 100100--10001000 cells)cells)

CellsCells areare

the basic units of lifethe basic units of life,, building blocks of organismsbuilding blocks of organisms,,the smallest unit of living matterthe smallest unit of living matter , and, and the structuralthe structuraland functional units of all living organismsand functional units of all living organisms..

The smallest structural, functional and biologicalThe smallest structural, functional and biologicalunit of an organism that is capable of independentunit of an organism that is capable of independentfunctioning, consisting of one or more nuclei,functioning, consisting of one or more nuclei,cytoplasm, and various organelles, all surroundedcytoplasm, and various organelles, all surroundedby aby a semipermeablesemipermeable cell membranecell membrane

Micrographia. The description ofthese cells (which were actually

non-living cell walls), without

structure or function understanding,

was published in Micrographia. His

cell observations gave no indicationof the nucleus and other organelles

found in most living cells.

2. History

Robert Hooke. The cell was first discovered by RobertHooke in 1665 examining very thin slices of cork and saw

a multitude of tiny pores that remarked looked like the

walled compartments of a honeycomb which was then

called cells

Significant Events in Cell BiologySignificant Events in Cell Biology 16551655 -- Robert Hooke gives first description of a cork tree cell.Robert Hooke gives first description of a cork tree cell.

16741674 -- Leeuwenhoek views protozoa.Leeuwenhoek views protozoa.

16831683 -- Leeuwenhoek views bacteria.Leeuwenhoek views bacteria.

18311831 -- Robert Brown was first to identify theRobert Brown was first to identify the nucleusnucleusas an importantas an importantcell component.cell component.

18381838 -- SchleidenSchleiden and Schwann introduce what would become the Celland Schwann introduce what would become the CellTheory.Theory.

18571857 -- KollikerKollikerdescribesdescribes mitochondriamitochondria..

18691869 -- MiescherMiescher isolates DNA for the first time.isolates DNA for the first time.

18821882 -- KockKockidentifies bacteria.identifies bacteria.

18981898 -- Golgi discovers theGolgi discovers the Golgi apparatusGolgi apparatus..

19311931 -- Ruska builds the first Transmiss ion Electron Microscope.Ruska builds the first Transmission Electron Microscope.

19531953 -- Watson and Crick propose structure of DNAWatson and Crick propose structure of DNA doubledouble--helixhelix..

19651965 -- First commercial Scanning Electron Microscope produced.First commercial Scanning Electron Microscope produced.

19971997 -- First sheepFirst sheep clonedcloned..

19981998 -- Mice cloned.Mice cloned.

20032003 -- Human genome DNA sequence draft completed.Human genome DNA sequence draft completed.


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3.3. Cell TheoryCell TheoryCell theoryCell theory refers to the idea thatrefers to the idea that cells are thecells are thebasic unit of structure in every living thingbasic unit of structure in every living thing..

1.1. All organisms are composed of one or more cells.All organisms are composed of one or more cells.2.2. The cell is the basic living unit of organization for all livingThe cell is the basic living unit of organization for all living

thingsthings3.3. All cells arise from preexisting cellsAll cells arise from preexisting cells4.4. Cells contain all of the hereditary informationCells contain all of the hereditary information

The modern tenets of the Cell Theory include:The modern tenets of the Cell Theory include:1.1. all known living things are made up of cells.all known living things are made up of cells.2.2. the cell is structural & functional unit of all living things.the cell is structural & functional unit of all living things.3.3. all cells come from preall cells come from pre--existing cells by d ivision.existing cells by d ivision.

(Spontaneous Generation does not occur).(Spontaneous Generation does not occur).4.4. cells contains hereditary information which is passed fromcells contains hereditary information which is passed from

cell to cell dur ing cell division.cell to cell dur ing cell division.5.5. All cells are basically the same in chemical composition.All cells are basically the same in chemical composition.6.6. all energy flow (metabolism & biochemistry) of life occursall energy flow (metabolism & biochemistry) of life occurs

within cells.within cells.

4.4. TYPE OF CELLSTYPE OF CELLS

Cells can be subdivided into two subcategories:Cells can be subdivided into two subcategories:Prokaryotes & Eukaryot esProkaryotes & Eukaryot es

ProkaryotesProkaryotes::

lacklack a nucleusa nucleus (though they do have circular(though they do have circularDNA) andDNA) and

lacklack other membraneother membrane--bound organellesbound organelles(though they do contain(though they do contain ribosomesribosomes))

Bacteria andBacteria and ArchaeaArchaea are two divisions ofare two divisions ofprokaryotes.prokaryotes.

EukaryotesEukaryotes::

have distincthave distinct nucleinuclei andand membranemembrane--boundboundorganellesorganelles (mitochondria, chloroplasts,(mitochondria, chloroplasts,lysosomeslysosomes, rough and smooth endoplasmic, rough and smooth endoplasmic

reticulum, vacuoles).reticulum, vacuoles). possess organized chromosomes which storepossess organized chromosomes which store

genetic material.genetic material.

Two types of cells


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5.5. Animal and Plant cellsAnimal and Plant cells Both animal (A) and plant (B) cells haveBoth animal (A) and plant (B) cells have

a cell membrane (1),a cell membrane (1), nucleus (2), andnucleus (2), and

cytoplasm (3).cytoplasm (3).

Plant cells havealso a cell wall (4) and certain organelles,

notably chloroplasts,

which are unique toplant cells

III. PLANT CELL STRUCTUREIII. PLANT CELL STRUCTURE1. Cytoplasm2. Nucleoplasm3. Nucleus

largest organelle4. Nucleolus

(nuceioli plural) ChromatinChromatin

ChromosomesChromosomes

5. Ribosomes6. Endoplasmic

reticulum (ER) Smooth ER Rough ER

7. Golgi Complex8. Lysosomes(in

animals)

9. Vacuoles10. Mitochondria11. Chloroplasts12. Other plastids13. Microbodies14. Cytoskeleton15. Cell Wall16. Membrane

An electron micrograph of a wheat leaf cell. Note the ring ofcytoplasm-containing chloroplast that surrounds a large vacuole(courtesy of Kitty Plaskitt)


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1.1. CytoplasmCytoplasm material outside of nucleus, consistsmaterial outside of nucleus, consists

of fluid and particl es and membranesof fluid and particl es and membranes

2.2. NucleoplasmNucleoplasm material inside nucleusmaterial inside nucleus

3.3. NucleusNucleus largest organellelargest organelle Nuclear envelopeNuclear envelope Double MembraneDouble Membrane envelope withenvelope with

many nuclearmany nuclear porespores

FunctionFunction: holds the DNA: holds the DNA

PartsParts: Nucleolus: Nucleolus

4.4. NucleolusNucleolus ((nuceiolinuceioli plural)plural) Site of ribosome assemblySite of ribosome assembly

RibosomesRibosomes leave through poresleave through poresand are found free in theand are found free in thecytoplasm or associated withcytoplasm or associated with

Endoplasmic reticulumEndoplasmic reticulum

ChromatinChromatin Seen in cells thatSeen in cells that

are not dividingare not dividing DecondensedDecondensed DNADNA

associated withassociated withRNA and proteinsRNA and proteins

ChromosomesChromosomes Seen in cells thatSeen in cells that

are dividingare dividing Condensed DNA inCondensed DNA in

a highly organizeda highly organizedand compact formand compact form

nucleolusnucleolus:: rRNArRNA;;

ribosome synthesisribosome synthesis

Genetic material in the Nucleus

5.5. RibosomesRibosomes Protein manufacture,Protein manufacture, organelles that are part of the proteinorganelles that are part of the protein

synthesis machinerysynthesis machinery

Free :Free :cytosolcytosol; protein function; protein function inincellcell BoundBound: endoplasmic reticulum; membranes,: endoplasmic reticulum; membranes,

organelles, andorganelles, and exportexport FunctionFunction: makes proteins: makes proteins

sets of membranes continuoussets of membranes continuouswith the nuclear and plasmawith the nuclear and plasmamembranesmembranes

Membranes act to divide upMembranes act to divide upthe cytoplasm intothe cytoplasm intocompartments and channelscompartments and channels

FunctionFunction: The internal delivery: The internal deliverysystem of the cellsystem of the cell

Smooth ERSmooth ER nono ribosomesribosomes;;

Functions: synthesis of lipids,Functions: synthesis of lipids,phosolipidphosolipid& steroid ;& steroid ; metabolismmetabolismof carbohydrates; detoxification ofof carbohydrates; detoxification ofdrugs and poisonsdrugs and poisons

Rough ERRough ER withwith ribosomesribosomes;;

Functions: synthesis ofFunctions: synthesis of secretorysecretoryproteins (proteins (glycoproteinsglycoproteins) &) &membrane productionmembrane production

6. Endoplasmic reticulum (ER)


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7.7. Golgi ComplexGolgi Complex CisternaeCisternae: flattened membranous sacs: flattened membranous sacs (look like a(look like a

stack of pita bread)stack of pita bread) FunctionFunction: packages, modifies, and transports: packages, modifies, and transports

materials to different location inside/outside of the cellmaterials to different location inside/outside of the cell

sets of smooth membranes derived from the ER Functions: sorting and modifying proteins, ultimately

transports products to the plasma membrane or are

stored in the cytoplasm, also produces the lysosomes

8.8. LysosomesLysosomes (in(inanimals)animals) sac of hydrolytic enzymessac of hydrolytic enzymes

((powerful digestivepowerful digestive

enzymesenzymes); digestion of); digestion ofmacromoleculesmacromolecules

Function as the cellsFunction as the cellsrecycling center byrecycling center by

digesting worndigesting worn--outout

organelles or materialsorganelles or materialsingested by cell:ingested by cell:

PhagocytosisPhagocytosis

AutophagyAutophagy: recycle cells own: recycle cells ownorganic materialorganic material

TayTay--SachsSachs disease~lipiddisease~lipid--digestion disorderdigestion disorder

Rheumatoid arthritis is due to damage in joints due to leaky

white blood cell lysosomes

9.9. VacuolesVacuoles

membranemembrane--bound sacsbound sacs(larger than vesicles)(larger than vesicles)

Food (Food (phagocytosisphagocytosis))

Contractile (pumpContractile (pumpexcess water)excess water)

Central (storage inCentral (storage inplants)plants) tonoplasttonoplast

membranemembrane

10.10. MitochondriaMitochondria quantity in cellquantity in cell

correlated withcorrelated withmetabolic activity;metabolic activity;

cellular respiration;cellular respiration;

double membranousdouble membranous((phospholipidphospholipid););

cristaecristae/matrix;/matrix;

intermembraneintermembrane space;space;

contain own DNAcontain own DNA


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11.11. ChloroplastsChloroplasts Type of plastid;Type of plastid; Site of photosynthesis & Also doubleSite of photosynthesis & Also double

membrane boundmembrane bound thylakoidsthylakoids (flattened disks);(flattened disks); granagrana (stacked(stacked

thylakoidsthylakoids);); stromastroma;; Pigments (Pigments (chorophylchorophyl and others)and others) Also have their own DNA moleculesAlso have their own DNA molecules

12.12. Other plastidsOther plastids

leukoplastsleukoplasts

store starchstore starchand areand arecolorless,colorless,andand

chromoplastschromoplasts

store coloredstore coloredpigmentspigments

13.13. MicrobodiesMicrobodies Various organelles whichVarious organelles which

regulate differentregulate differentmetabolic reactions suchmetabolic reactions suchasas

peroxisomesperoxisomes , s, singleinglemembranemembrane break down hydrogenbreak down hydrogen

peroxideperoxide then converted tothen converted towaterwater,, Metabolism of fattyMetabolism of fattyacids; detoxification ofacids; detoxification ofalcohol (liver)alcohol (liver)

glyoxysomesglyoxysomes areareimportant inimportant in germiniatinggerminiatingseedsseeds

Organelles involved withOrganelles involved withEnergy Production andEnergy Production andUtilizationUtilization

14.14. The CytoskeletonThe Cytoskeleton Fibrous network inFibrous network in

cytoplasmcytoplasm Support, cell motility,Support, cell motility,

biochemical regulationbiochemical regulation Microtubules:Microtubules:

thickest;thickest; tubulintubulin protein;protein; shape, support, transport,shape, support, transport,

chromosome separationchromosome separation

Microfilaments :Microfilaments : Thinnest;Thinnest;

actinactin protein filaments;protein filaments; motility, cell division,motility, cell division,

shapeshape Intermediate filaments:

middle diameter;

keratin; shape, nucleus

anchorage


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15.15. Cell WallCell Wall

16.16. MembraneMembrane The membrane thatThe membrane that

surrounds a cell issurrounds a cell ismade up of proteinsmade up of proteinsand lipids.and lipids.

Depending on theDepending on themembranes locationmembranes locationand role in the body,and role in the body,lipids can make uplipids can make upanywhere from 20 toanywhere from 20 to80 percent of the80 percent of themembrane, with themembrane, with theremainder beingremainder beingproteins.proteins.

Cholesterol, which is not found in plant cells, is a typeCholesterol, which is not found in plant cells, is a typeof lipid that helps stiffen the membrane.of lipid that helps stiffen the membrane.

IV. STEM CELLSIV. STEM CELLS

Definitions

Stem cells undifferentiated cells that havethe ability to: divide for indefinite periods in culture to become specialized cells

Differentiation the process whereby cells become

specialized

Produces stems cells with decreasingpotential

What are Stem cells?


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PotentialsPotentials

Totipotenthaving unlimited capability. Totipotentcells have the capacity to specialize intoextraembryonic membranes and all cellsof the embryo.

Pluripotentcapable of giving rise to most tissues ofan organism.

Multipotentcapable of giving rise to many tissues ofan organism.

Stem cells

undifferentiated cells that divide and give rise to

cells that differentiate into

specialized cells of plantand animal tissues

Two types of stem cells Embryonic (ES) Adult (non-embryonic)

(AS)

Embryonic Stem CellsEmbryonic Stem Cells

1.1. Embryos are the result ofEmbryos are the result of In VitroIn Vitro

FertilizationFertilization (IVF)(IVF)

2.2. Cells are taken from the Inner CellCells are taken from the Inner CellMass (ICM) of aMass (ICM) of a blastocystblastocyst

3.3. ICM cells are nourished in aICM cells are nourished in a petripetri dish indish inan incubatoran incubator

4.4. Cells are given different types ofCells are given different types ofFactors/chemicalsFactors/chemicals

These cells can give rise toThese cells can give rise to mostmost typestypesof cellsof cells

4040

Embryonic Stem CellsEmbryonic Stem Cells


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4141

Adult Stem CellsAdult Stem Cells

Adult tissues reported to containAdult tissues reported to containstem cells include:stem cells include: brain, bonebrain, bonemarrow, peripheral blood, bloodmarrow, peripheral blood, bloodvessels, skeletal muscle, skin andvessels, skeletal muscle, skin andliverliver..

There are a very small number ofThere are a very small number ofstem cells in each tissuestem cells in each tissue

Stem Cells differ byStem Cells differ by

OriginOrigin

EmbryonicEmbryonic

AdultAdult

DifferentDifferentpotentialspotentials

TotipotentTotipotent

PluripotentPluripotent

MultipotentMultipotent

In plants, stem cells are localized inIn plants, stem cells are localized inmeristemsmeristems

MBoC (4) figure 21-111 and 112 Garland Publishing

Shoot apical meristem, Root apical meristem, Lateral oraxial meristems & Floral meristem

Shoot apicalmeristem

Shoot apicalmeristem

Cell fate in rootCell fate in rootis determinedis determinedby positionby position

Cells leavemeristem and enterfiles (colors) anddifferentiate intospecific fates (stele,endodermis, cortex

etc.)

Meristem

renewal

Differentiation

endodermis

cortex stele


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Cells of adult plants remain totipotent:Cells of adult plants remain totipotent:cloning a carrotcloning a carrot

Moore et al Figure 9.2Wm C Brown Publishing

1 mm3 fragments (explants)from adult root

Culture explants in liquid culture mediumCells dedifferentiate and begin to divide,forming callus tissue

Induce with hormones to initiate shootand root formation

Culture embroid in liquid culture,then agar

Move to soil

Regenerated adult plant

Cells from young animal embryos areCells from young animal embryos arealsoalso totipotenttotipotent

Totipotent -capable offorming alldifferentiatedcells of adult

Pluripotent -capable offorming morethan 1differentiated celltype

Differentiation occurs in three stagesDifferentiation occurs in three stages

Fertilized animal eggs and early embryonic cells can giveFertilized animal eggs and early embryonic cells can give

rise to all the different cell types of the body, they arerise to all the different cell types of the body, they areconsidered considered totipotentotipotentt.. Identical twinsIdentical twins

Cell fates become progressively restricted duringCell fates become progressively restricted during

development, a process calleddevelopment, a process calleddifferentiation.differentiation.

Differentiation occurs in three stagesDifferentiation occurs in three stages SpecificationSpecification

Fate is not absoluteFate is not absolute

Cell identity subject to changeCell identity subject to change

DeterminationDetermination Fate is fixed, and cannot change in response toFate is fixed, and cannot change in response to

environmentenvironment

DifferentiationDifferentiation Changes in cell structure and functionChanges in cell structure and function

How do cells loseHow do cells lose totipotencytotipotency??

Gross DNA rearrangement or loss (rare?)Gross DNA rearrangement or loss (rare?) BB--lymphocytes (make antibodies) splice geneslymphocytes (make antibodies) splice genes

encodingencoding IgGIgG HCHC

Mammalian erythrocytes (red blood cells) enucleateMammalian erythrocytes (red blood cells) enucleate

Terminal differentiation (some tissues/cells)Terminal differentiation (some tissues/cells) Loss of cell division capacity: muscle, neurons, othersLoss of cell division capacity: muscle, neurons, others

Altered gene expression (most common)Altered gene expression (most common) Transcriptional regulation by transcription factors,Transcriptional regulation by transcription factors,

Reversible, in principle (with difficulty)Reversible, in principle (with difficulty)


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Stem cells that resupply differentiated cells areStem cells that resupply differentiated cells arepluripotentpluripotent: example blood: example blood

Hemopoetic stem cell:Divides to renew itselffor lifespan of animalCan form a limitednumber of cell types(pleuripotent)But not differentiated

Blood cells must berenewed but notcapable of cell division(red blood cells lack anucleus)

ECB 21-39

Importance of Stem CellsImportance of Stem Cells

Stem cells,Stem cells,

directed to differentiate into specific celldirected to differentiate into specific celltypes,types,

offer the possibility of a renewableoffer the possibility of a renewablesource of replacement cells and tissuessource of replacement cells and tissues

to treat diseases includingto treat diseases including Parkinson'sParkinson'sandand Alzheimer's diseasesAlzheimer's diseases,, spinal cordspinal cordinjuryinjury,, strokestroke,, burnsburns,, heart diseaseheart disease,,

diabetesdiabetes,, osteoarthritisosteoarthritis, and, and rheumatoidrheumatoidarthritisarthritis..

http://stemcells.nih.gov/

Loss of dopamine-producing cells in the brain

Goal: stem cell replacement

Mouse embryonic stemcells --cured mouseParkinsons disease(model system)

Parkinsons diseaseParkinsons disease

Using embryonic stem cells from patient would eliminate risk of rejection

Hope for treatment of diabetes, osteoarthritis etc.


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V. CELL CASEV. CELL CASE MostMost blood cellsblood cells develop from cells in the bonedevelop from cells in the bone

marrow calledmarrow called stem cellsstem cells. Bone marrow is the. Bone marrow is thesoft material in the center of most bones.soft material in the center of most bones.

The bone marrow makes abnormalThe bone marrow makes abnormal white bloodwhite bloodcellscells (leukemia cells) in a person with leukemia(leukemia cells) in a person with leukemia

Leukemia cells don't die, and may crowd outLeukemia cells don't die, and may crowd outnormal white blood cells, red blood cells, andnormal white blood cells, red blood cells, andplatelets which makes it hard for normal bloodplatelets which makes it hard for normal bloodcells to do their work.cells to do their work.

The white blood cells that form from myeloidblasts are different from the white blood cellsthat form from lymphoid blasts.

The myeloid stem cell develops

into

1.1. Red blood cellsRed blood cells that carrythat carry

oxygen and other materialsoxygen and other materialsto all tissues of the bodyto all tissues of the body

2.2. White blood cellsWhite blood cells that fightthat fight

infection and diseaseinfection and disease

3.3. PlateletsPlatelets that help preventthat help preventbleeding by causing bloodbleeding by causing bloodclots to form.clots to form.

The lymphoid stem cell develops into a lymphoblast celland then into one of three types of lymphocytes (whiteblood cells)

1.1. B lymphocytesB lymphocytes that make antibodies to help fightthat make antibodies to help fightinfection.infection.

2.2. T lymphocytesT lymphocytes that help B lymphocytes make antibodiesthat help B lymphocytes make antibodies

to help fight infection.to help fight infection.

3.3. Natural killer cellsNatural killer cells that attack cancer cells and viruses.that attack cancer cells and viruses.

Irradiated hostsurvives after bonemarrow transplant

New blood cellshave MHC type of

marrow donor

Bone marrow containsBone marrow contains hemopoietichemopoietic stemstemcells for blood cellscells for blood cells

Inject bone marrowfrom healthy donorof different MHCtissue type

X-irradiation stops productionof blood forming cells

Lethal without treatment

MBoC (4) figure 22-34 Garland Publishing

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Lect9F Life and Cell 2011