lect9f life and cell 2011
TRANSCRIPT
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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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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