CellsCells

Inside and OutInside and Out

Cell TheoryCell Theory

English scientist Robert Hooke used a English scientist Robert Hooke used a crude microscope to look at a slice of crude microscope to look at a slice of corkcork.. He saw little boxes that reminded him of the He saw little boxes that reminded him of the

small rooms that monks lived in – Cellssmall rooms that monks lived in – Cells

Cell TheoryCell Theory

Later the observations of scientists Later the observations of scientists Schleiden, Schwann and Virchow led to Schleiden, Schwann and Virchow led to what we call the what we call the Cell TheoryCell Theory:: All living things are composed of one or All living things are composed of one or

more cellsmore cells Cells are the basic units of structure and Cells are the basic units of structure and

function in organismsfunction in organisms All cells arise from existing cellsAll cells arise from existing cells

Size Chart

Atom

Molecule

Organelle

Cell

Tissue

Organ

Organ System

Organism

Population

Community

Ecosystem

Cell SizeCell Size

Having many small cells is more efficient Having many small cells is more efficient than having a few large cellsthan having a few large cells

Small cells have larger surface to volume Small cells have larger surface to volume ratios than large onesratios than large ones So, substance exchange is faster in small So, substance exchange is faster in small

cells than in large.cells than in large.

Surface to Volume Ratio Surface to Volume Ratio ExampleExample

Surface area Equation on a cubeSurface area Equation on a cube LL2 2 X 6 X 6

Volume Equation of a cubeVolume Equation of a cube LL2 2 X HX H

MagnificationMagnification

Light microscopeLight microscopeVisible light passes through objectVisible light passes through objectA Lens magnifies the imageA Lens magnifies the image

MagnificationMagnificationMaking an image seem larger than what it Making an image seem larger than what it

isisResolutionResolution

What measures the clarity of an object What measures the clarity of an object What limits a particular type of scopeWhat limits a particular type of scope

MagnificationMagnificationElectron MicroscopeElectron Microscope

100,000 X 100,000 X magnification powermagnification power

Scanning Electron Scanning Electron Microscope (SEMMicroscope (SEM))

Allows for better Allows for better resolutions on the resolutions on the surface of an surface of an objectobject

Shows object in Shows object in 3D3D

Good for Good for observing living observing living organismsorganisms

MagnificationMagnification

Electron Electron MicroscopesMicroscopes Transmission Transmission

Electron Electron Microscope (TEM)Microscope (TEM)

Observer to sees Observer to sees through cellsthrough cells

allows the observer to allows the observer to see specimen's see specimen's internal structureinternal structure

Features Common to All CellsFeatures Common to All Cells

Cell MembraneCell Membrane All cells share this outer boundaryAll cells share this outer boundary This membrane This membrane encloses and separates encloses and separates the the

interior of the cell – the cytoplasminterior of the cell – the cytoplasm The cell membrane also The cell membrane also regulates regulates what what

enters and leaves the cellenters and leaves the cell

Features Common to All CellsFeatures Common to All Cells

Cytoplasm (Cyto= cell, -plasm= formative Cytoplasm (Cyto= cell, -plasm= formative material)material) Everything betweenEverything between plasma membrane and nucleus plasma membrane and nucleus

or nucleoid or nucleoid region.region.

Cytoskeleton (Cyto= cell, -skeleton= structural Cytoskeleton (Cyto= cell, -skeleton= structural framework)framework) Structure made ofStructure made of microfibers & microtubules microfibers & microtubules

within the cytoplasm that suspends the cells within the cytoplasm that suspends the cells structuresstructures

Most cells have Most cells have ribosomesribosomes Cellular Structures on whichCellular Structures on which proteins proteins are madeare made

ProkaryotesProkaryotes Bacteria CellsBacteria Cells

Have no Have no nucleusnucleus Evolved before eukaryotic cellsEvolved before eukaryotic cells Structures Common to ProkaryotesStructures Common to Prokaryotes

Nucleoid region-Nucleoid region- where the chromosome is where the chromosome is ribosomes- ribosomes- protein synthesisprotein synthesis Cell membrane- Cell membrane- “gate keeper”“gate keeper” Cell wall (different than plants)Cell wall (different than plants)- - supportsupport Some have capsules outside wall- Some have capsules outside wall- resistance resistance

to antibioticsto antibiotics Pili- Pili- exchange of genetic infoexchange of genetic info Flagella- Flagella- movementmovement

ProkaryotesProkaryotes

EukaryotesEukaryotes

Plant and Animal CellsPlant and Animal Cells Cells are Cells are more complexmore complex than prokaryotic cells than prokaryotic cells

Much like Prokaryotes Eukaryotic CellsMuch like Prokaryotes Eukaryotic Cells have a have a cell walcell wall (plants/protists/fungi)l (plants/protists/fungi) have a have a plasma membraneplasma membrane have have Cytoplasm Cytoplasm havehave ribosomes ribosomes

But within their cytoplasm eukaryotes haveBut within their cytoplasm eukaryotes have OrganellesOrganelles CytosolCytosol - fluid in cytoplasm - fluid in cytoplasm

Major Organelles to knowMajor Organelles to know

Cytoskeleton- Cytoskeleton- support & protectionsupport & protectionCell membrane- Cell membrane- “gate keeper” controls what enters or “gate keeper” controls what enters or

leaves the cellleaves the cellNucleus- Nucleus- holds the chromosomes, directs cellholds the chromosomes, directs cellEndoplasmic Reticulum- Endoplasmic Reticulum- transport & protein formationtransport & protein formationGolgi Apparatus- Golgi Apparatus- packages thingspackages thingsLysosomes- Lysosomes- hold digestive enzymes, “suicide sac”hold digestive enzymes, “suicide sac”Vesicles- Vesicles- storagestorageMitochondria- Mitochondria- “Power house” respiration, ATP energy“Power house” respiration, ATP energyCell Wall- Cell Wall- support, protectionsupport, protectionChloroplasts- Chloroplasts- photosynthesis, make glucosephotosynthesis, make glucoseCentral Vacuole- Central Vacuole- storage, especially of waterstorage, especially of waterRibosomes- Ribosomes- protein makingprotein making

CytoskeletonCytoskeleton

Provides Provides interior interior frameworkframework to support to support cell cell

Made of network of Made of network of protein fibersprotein fibers tied to tied to the plasma the plasma membrane.membrane.

CytoskeletonCytoskeleton

There are There are three kindsthree kinds of cytoskeleton fibers of cytoskeleton fibers MicrofilamentsMicrofilaments (or Actin Fibers) (or Actin Fibers)

Made of protein Made of protein actinactin Works in theWorks in the shape and movement shape and movement of a cellof a cell

MicrotubulesMicrotubules Tiny tubules made up Tiny tubules made up tubulin tubulin protein protein Highway forHighway for transportation transportation of info. from nucleus to parts of info. from nucleus to parts

of the cellof the cell

Intermediate FibersIntermediate Fibers Rope-like fibers where Rope-like fibers where enzymes and ribosomes enzymes and ribosomes anchor in anchor in

the cellthe cell

Cell MembraneCell Membrane

Phospholipid bilayerPhospholipid bilayer - barrier separating inside of cell - barrier separating inside of cell (cytoplasm) from outside(cytoplasm) from outside

Selectively permeableSelectively permeable (penetrable) - controls what (penetrable) - controls what enters & leaves cellenters & leaves cell

Proteins Embedded in the Proteins Embedded in the Plasma MembranePlasma Membrane

** Proteins are macromolecules made of amino ** Proteins are macromolecules made of amino acidsacids

Some proteins embed in the plasma membraneSome proteins embed in the plasma membrane EnzymesEnzymes Transport ProteinsTransport Proteins Receptor ProteinsReceptor Proteins

Must have both polar & non polar ends to embed Must have both polar & non polar ends to embed in the membranein the membrane

NucleusNucleus

Nucleus and mitochondria containNucleus and mitochondria contain genes genesNucleus consists of:Nucleus consists of:

EnvelopeEnvelope Double Double membranemembrane Pores let messages in and outPores let messages in and out

ChromatinChromatin DNADNA ProteinProtein

NucleolusNucleolus ProducesProduces rRNA rRNA rRNA with proteins makes up ribosomesrRNA with proteins makes up ribosomes

NucleusNucleus

Endoplasmic Reticulum Endoplasmic Reticulum (endo = (endo = Inside, plasm = formed material)Inside, plasm = formed material) Major system of internal membranes- Major system of internal membranes-

move proteinsmove proteins and other stuff through and other stuff through cellcell Is a lipid bilayer with embedded proteinsIs a lipid bilayer with embedded proteins Makes steroids,Makes steroids, lipids lipids Detoxifies chemicalsDetoxifies chemicals

Endoplasmic Reticulum (ER)Endoplasmic Reticulum (ER)

Rough ERRough ER Has ribosomes Has ribosomes embedded so looks “rough”embedded so looks “rough” Processes proteinsProcesses proteins

Smooth ERSmooth ER No ribosomesNo ribosomes embedded so looks “smooth” embedded so looks “smooth” Makes lipids and breaks down toxic chemicals Makes lipids and breaks down toxic chemicals

Golgi Apparatus/LysosomesGolgi Apparatus/Lysosomes

Golgi ApparatusGolgi Apparatus Flattened pancake like membrane-bound sacs- theFlattened pancake like membrane-bound sacs- the packaging packaging

distribution distribution center of the cellcenter of the cell

Lysosomes/VesiclesLysosomes/Vesicles

Lysosomes (lyso-breaking, -some=body)• Small spherical organelles- • hold digestive enzymes

Work with Golgi to produce, package and distribute protiens

Vesicles• Small bubble-like membrane bound sacs• carry material from ER to Golgi and out of cell

Some will become lysosomes

Here’s the Protein FlowHere’s the Protein Flow

MitochondriaMitochondria

Harvests energy fromHarvests energy from organic compound organic compound ((sugarssugars) ) to make ATPto make ATP ATP: energy ATP: energy “Money”“Money” in the cells in the cells CCellular respirationellular respiration

Most eukaryote cells contain mitochondriaMost eukaryote cells contain mitochondriaDouble membraneDouble membrane

Big bag stuffed in smaller bagBig bag stuffed in smaller bag Folds of inner bag = Folds of inner bag = cristaecristae

Space inside inner bag called Space inside inner bag called matrixmatrix Holds enzymes andHolds enzymes and DNA DNA This DNA ONLY inherited from This DNA ONLY inherited from mommom

MitochondriaMitochondria

Organelles Common to PlantsOrganelles Common to Plants

Plants contain all of the organelles now Plants contain all of the organelles now mentioned plus morementioned plus more

Organelles Only in Plants (not animals)Organelles Only in Plants (not animals) Cell WallCell Wall ChloroplastChloroplast Central VacuoleCentral Vacuole

Cell WallCell Wall

Surrounds the cell membraneSurrounds the cell membraneMade of Made of proteinsproteins and and carbohydratescarbohydrates

Cellulose - polysaccharide(poly=many, Cellulose - polysaccharide(poly=many, saccharide=sugars) cellulose can NOT be digested saccharide=sugars) cellulose can NOT be digested by all by all us,us, but some can. but some can.

Supports and Maintains the shape of a cellSupports and Maintains the shape of a cellProtects from damageProtects from damage

ChloroplastsChloroplastsPlant cells contain mitochondria to produce the Plant cells contain mitochondria to produce the

energy “bucks” (ATP), energy “bucks” (ATP), ANDAND they contain they contain chloroplasts to make the glucose the chloroplasts to make the glucose the mitochondria “burns” to make the ATPmitochondria “burns” to make the ATP

Chloroplasts use light energy to convert carbon Chloroplasts use light energy to convert carbon dioxide and water into sugar, oxygen and dioxide and water into sugar, oxygen and energy (ATP)energy (ATP)

Also found in Also found in algaealgae and some and some protozoans.protozoans.ChloroplastsChloroplasts

have have two membranestwo membranes have have enzymes & DNAenzymes & DNA

ChloroplastsChloroplasts

Central VacuoleCentral Vacuole

LargestLargest organelle in a plant cell organelle in a plant cell Contains Contains ionsions (charged atoms), (charged atoms), nutrientsnutrients

(macromolecules), and (macromolecules), and wasteswastes When full, makes cell rigid which When full, makes cell rigid which

enables the plant to stand upright.enables the plant to stand upright.

Plant CellPlant Cell

The Endosymbiotic HypothesisThe Endosymbiotic HypothesisEvolution of the Eukaryotic cell Evolution of the Eukaryotic cell

– (with mitochondria and – (with mitochondria and chloroplasts)chloroplasts)Theory:Theory: one large prokaryotic one large prokaryotic

cell ingested another which cell ingested another which became mitochondria and/or became mitochondria and/or chloroplast in the now chloroplast in the now eukaryotic cell.eukaryotic cell.

EvidenceEvidenceBoth are similar to bacteria in size Both are similar to bacteria in size

and shapeand shapeBoth have a double membraneBoth have a double membrane

Outer from being taken into cellOuter from being taken into cellInner from original bacterial cellInner from original bacterial cell

Contain DNA in loop like bacteriaContain DNA in loop like bacteriaContain ribosomes - make Contain ribosomes - make

proteinsproteinsRNA in ribosomes like bacterial RNA in ribosomes like bacterial

cells cells

The Endosymbiotic TheoryThe Endosymbiotic Theory