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Bell Ringer 12/1/11Bell Ringer 12/1/11 What is the person on What is the person on
the left looking through?the left looking through? What is the person on What is the person on
the right looking the right looking throughthrough
What point is this What point is this cartoon making?cartoon making?
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html
Get ready for notes!Get ready for notes!
The The Story Story
of of CellsCells
What are cells?What are cells?The Building Blocks of The Building Blocks of
LifeLife
The cell is the smallest The cell is the smallest structural unit capable of structural unit capable of performing life functions. performing life functions.
Cell TriviaCell Trivia
The average human being is The average human being is composed of around 100 Trillion composed of around 100 Trillion individual cells!!!individual cells!!!
The egg yolk from an ostrich egg is The egg yolk from an ostrich egg is the largest cell. They are about a half the largest cell. They are about a half foot long. foot long.
It would take as many as 50 cells to It would take as many as 50 cells to cover the area of a dot on the letter cover the area of a dot on the letter “i”“i”
Discovery of CellsDiscovery of Cells16651665- English Scientist, - English Scientist, Robert HookeRobert Hooke, discovered cells , discovered cells
while looking at a thin slice of cork (bark of tree)while looking at a thin slice of cork (bark of tree)– He described the cells as tiny boxes or a honeycombHe described the cells as tiny boxes or a honeycomb– He thought that cells only existed in plants and fungiHe thought that cells only existed in plants and fungi
The Microscope! The Microscope!
1673- Anton von Leuwenhoek, invented the microscope and observed pond scum and discovered single celled organisms
•He called them “animalcules”He called them “animalcules”•He also observed blood cells from fish, birds, frogs, dogs, He also observed blood cells from fish, birds, frogs, dogs, and humansand humans•Therefore, it was known that cells are found in animals as Therefore, it was known that cells are found in animals as well as plantswell as plants
Where does life come Where does life come from?from?
Old TheoryOld Theory - Spontaneous - Spontaneous GenerationGeneration
Life spontaneously happens: Life spontaneously happens:
Life comes from non-life Life comes from non-life Examples: Examples:
– Mice from cloth sacks and grains.Mice from cloth sacks and grains.– Maggots from rotting meat.Maggots from rotting meat.
REALLY?
Where does life come Where does life come from?from? Much doubt existed around Much doubt existed around Spontaneous Spontaneous
GenerationGeneration Conclusively Conclusively disproved by Louis Pasteurdisproved by Louis Pasteur
+
=?
Ummm, I don’t think so!!!
Where does life come Where does life come from?from?
1858- Rudolf Virchow1858- Rudolf Virchow, German physician, after , German physician, after extensive study of cellular pathology, concluded that extensive study of cellular pathology, concluded that cells must arise from preexisting cells.cells must arise from preexisting cells.
Biogenesis – Life can only be formed from existing life.
The Compound Light The Compound Light Microscope (review)Microscope (review)
LensesLenses LightLight You’ve used it!!You’ve used it!! Up to x1500Up to x1500
Our Microscope…Our Microscope…
The Electron Microscope The Electron Microscope (review)(review)
Biggest Biggest magnification magnification
(X 2,000,000)(X 2,000,000) 2 types 2 types (SEM and TEM)(SEM and TEM)
The Cell TheoryThe Cell Theory
1. All organisms are composed 1. All organisms are composed of one or more cells.of one or more cells.
2. The Cell is the smallest 2. The Cell is the smallest working unit of living things.working unit of living things.
3. All cells come from pre-3. All cells come from pre-existing cells through cell existing cells through cell division.division.
Examples of CellsExamples of Cells
Amoeba
Plants
Red Blood Cell
Nerve Cell
Bacteria
Two Types of CellsTwo Types of Cells
ProkaryotiProkaryoticc
EukeryoticEukeryotic
REMEMBER US
Prokaryotic CellsProkaryotic Cells ““Old School”Old School” Do notDo not have a have a
membrane-bound membrane-bound nucleus or organellesnucleus or organelles
Few internal Few internal structures (organelles)structures (organelles)
Usually one-celled Usually one-celled organisms like organisms like bacteriabacteria
Smaller in size (1-10 Smaller in size (1-10 um)um)
Eukaryotic CellsEukaryotic Cells ““New School”New School” They They dodo contain contain a membrane-bound nucleusa membrane-bound nucleus and and organellesorganelles and are and are
more complex.more complex. May be unicellular or multicellularMay be unicellular or multicellular Larger in size (10-100um)Larger in size (10-100um)
PlantAnimal
Cellular Organization Cellular Organization CopyCopy
ColoniesColonies = group of = group of genetically identical cells genetically identical cells living together (bacteria), living together (bacteria), can live independantlycan live independantly
MulticelluarityMulticelluarity = groups = groups of cells with specific roles of cells with specific roles in an organism in an organism – Tissues Tissues Organ Organ
Organ SystemOrgan System
Volvox
Pediastrum
Why are cells so small?Why are cells so small? Surface area-to volume ratioSurface area-to volume ratio: small : small
cells more efficientcells more efficient Small size = more surface areaSmall size = more surface area More surface area = easier transport More surface area = easier transport
of nutrients, oxygen, wasteof nutrients, oxygen, waste Pg. 73, Figure 4-5Pg. 73, Figure 4-5
DIFFUSIONDIFFUSION Movement of molecules from an area of Movement of molecules from an area of
higherhigher concentration to an area of concentration to an area of lowerlower concentrationconcentration 1
43
2
How do things actually get How do things actually get in and out of the cell?in and out of the cell?
Through Through diffusion diffusion and and osmosisosmosis
Cell membrane Cell membrane and membrane and membrane structures act as structures act as the gatekeeperthe gatekeeper
How does diffusion occur?How does diffusion occur?
Passive TransportPassive Transport = doesn’t require = doesn’t require energyenergy
Concentration GradientConcentration Gradient = difference in = difference in concentration across a distanceconcentration across a distance
EquilibriumEquilibrium = concentration of molecules = concentration of molecules will be the same throughout the spacewill be the same throughout the space– Even at equilibrium molecules are still Even at equilibrium molecules are still
moving aroundmoving around [K] = concentration[K] = concentration
Simple DiffusionSimple Diffusion = diffusion across = diffusion across membranes, only certain molecules membranes, only certain molecules are allowed across through poresare allowed across through pores
http://www.indiana.edu/~phys215/lecture/lecnotes/lecgraphics/diffusion.gif
OSMOSISOSMOSIS
Diffusion of Diffusion of waterwater from from highhigh concentration concentration to to lowlow concentration concentration
Moves mostly through Moves mostly through passive transportpassive transport Water is always moving in and out of Water is always moving in and out of
your cellsyour cells
Which direction does the HWhich direction does the H22O O move?move?
If the solution is…If the solution is… HypotonicHypotonic Means [K] of solutes Means [K] of solutes
outside of cell is outside of cell is lower lower than than [K] of solutes in cytosol) [K] of solutes in cytosol) water moves water moves intointo the cell the cell– Cell will swell (get larger)Cell will swell (get larger)– Think hypThink hypoo……oo’s are round ’s are round
and chubby, like a plump and chubby, like a plump little celllittle cell
If the solution is…If the solution is…
HypertonicHypertonic [K] of solutes outside of [K] of solutes outside of
cell is cell is higherhigher than [K] of than [K] of solutes in cytosol solutes in cytosol
Water moves Water moves outout of the of the cellcell
Cell shrinks and shrivels Cell shrinks and shrivels upup
If the solution is…If the solution is…
IsotonicIsotonic [K] of solutes inside & [K] of solutes inside &
outside cell are =outside cell are = Water moves in & out at Water moves in & out at
equalequal rates rates
HOW CELLS DEAL W/ HOW CELLS DEAL W/ OSMOSISOSMOSIS
What happens if you live in a What happens if you live in a hypotonichypotonic environment? environment?
Get rid of extra water entering cells, Get rid of extra water entering cells, contractile vacuolecontractile vacuole
Get rid of extra solutes so less water Get rid of extra solutes so less water comes into cellcomes into cell
Turgor PressureTurgor Pressure = pressure of water = pressure of water against cell wall, occurs in against cell wall, occurs in hypotonichypotonic environmentenvironment
PlasmolysisPlasmolysis = water leaves cell & cell = water leaves cell & cell shrinks away from cell wall, occurs in shrinks away from cell wall, occurs in hypertonichypertonic environment environment
CytolysisCytolysis = bursting of cells , in a = bursting of cells , in a hypotonichypotonic environment too much environment too much water can move into cellwater can move into cell
-Are (typically) membrane-bound -Are (typically) membrane-bound structures with particular functions structures with particular functions within within eukaryotic eukaryotic cells.cells.-Are on the surface of cells as well as -Are on the surface of cells as well as inside the cell membrane.inside the cell membrane.
OrganellesOrganelles
Surrounding the Surrounding the CellCell
Cell Membrane Cell Membrane (Animal and Plant)(Animal and Plant)
Job:Job:– Boundary between the inside and the Boundary between the inside and the
outside of a celloutside of a cell – Is Is selectively permeableselectively permeable: (think Mr. : (think Mr.
Parker!)Parker!) Composed of:Composed of:
– Phospholipid bilayerPhospholipid bilayer– Transport proteinsTransport proteins
The model of the cell membrane is The model of the cell membrane is called the called the Fluid-Mosaic Model.Fluid-Mosaic Model. ((fluidfluid – phospholipids move w/in – phospholipids move w/in the membrane, the membrane, mosaicmosaic – patters – patters created proteins on membrane created proteins on membrane surface)surface)
Composition of a phospholipid
Cell Wall (Plant)Cell Wall (Plant) Most commonly found in plant cells & bacteriaMost commonly found in plant cells & bacteria Job:Job: Supports & protects cells, almost acts as a Supports & protects cells, almost acts as a
shellshell Composed of: Composed of: Cellulose fibrilsCellulose fibrils
Cillia and Flagella Cillia and Flagella (Animal and Prokaryotes)(Animal and Prokaryotes)
Job:Job: Helps cells move and aids in fluid transport Helps cells move and aids in fluid transport – CiliaCilia = many little hairs on the cell body = many little hairs on the cell body– FlagellaFlagella = few/one tail(s) = few/one tail(s)
Location:Location: On the exterior of the cell – in the cell matrix. On the exterior of the cell – in the cell matrix. Composed of:Composed of: membrane bound cylinders membrane bound cylinders
Inside the CellInside the Cell
Nucleus (Plant and Nucleus (Plant and Animal)Animal) Job:Job:
– Directs cell activities, Directs cell activities, storage of genetic info storage of genetic info (the brain of the cell)(the brain of the cell)
Location:Location: – Separated from the Separated from the
cytoplasm by the cytoplasm by the nuclear membrane nuclear membrane (envelope)(envelope)
Composed of:Composed of: – chromatin (DNA) which chromatin (DNA) which
is the blueprint for is the blueprint for proteinsproteins
Cytoplasm (Plant and Cytoplasm (Plant and Animal)Animal)
Job:Job: – Suspension of eukaryotic organellesSuspension of eukaryotic organelles– Site of numerous chemical reactionsSite of numerous chemical reactions
Location:Location: – Inside the cell membrane, inside individual Inside the cell membrane, inside individual
organellesorganelles Composed of:Composed of: CytosolCytosol
– Water, salts, protein filaments, and organic Water, salts, protein filaments, and organic compoundscompounds
– ~ 70% of a cell’s volume~ 70% of a cell’s volume
Endoplasmic Reticulum Endoplasmic Reticulum (ER) (Animal and Plant)(ER) (Animal and Plant)
Job:Job: site of cellular site of cellular chemical reactions, chemical reactions, assembly of proteinsassembly of proteins– Rough:Rough: protein protein
synthesis synthesis – Smooth:Smooth: numerous numerous
biochemical activities, biochemical activities, production and storage production and storage of lipidsof lipids
Location: Location: in the cytoplasmin the cytoplasm Composed of: Composed of: A highly A highly
folded membrane, folded membrane, Rough Rough ER ER has ribosomes has ribosomes imbedded in it for protein imbedded in it for protein synthesissynthesis
Ribosomes Ribosomes (Plant and Animal)(Plant and Animal)
Each cell contains Each cell contains thousandsthousands
Job: Job: Make proteinsMake proteins Location: Location: Found Found
on the ER, on the on the ER, on the nuclear envelope & nuclear envelope & floating throughout floating throughout the cellthe cell
Composed of:Composed of: simple structure of simple structure of 2 subunits:2 subunits:– RNA RNA – proteinprotein
Mitochondria Mitochondria (Plant and Animal)(Plant and Animal)
Job:Job: – Produces energy (ATP) Produces energy (ATP)
through chemical reactions through chemical reactions known as known as cellular respirationcellular respiration
– Breaks down sugar Breaks down sugar moleculesmolecules
Location:Location: – in the cytoplasmin the cytoplasm
Composed of:Composed of: – membranes (outer, and a membranes (outer, and a
highly-folded inner highly-folded inner membrane) and specific membrane) and specific enzymesenzymes
Facts:Facts: – Occur in various #s Occur in various #s
depending on cell functiondepending on cell function– Has its own DNAHas its own DNA
Golgi Apparatus Golgi Apparatus (Plant and Animal)(Plant and Animal)
Job: Job: Packaging Packaging plantplant– Sorts proteins into Sorts proteins into
packages and packs packages and packs them into vesicles to them into vesicles to be sent where they be sent where they are neededare needed
Location:Location: In the In the cytoplasmcytoplasm
Composed of:Composed of: System like a flat System like a flat stack of tubesstack of tubes
Lysosomes (Animal)Lysosomes (Animal) Job:Job:
– Digestive factory and breaks down waste (proteins, fats, and Digestive factory and breaks down waste (proteins, fats, and carbohydrates) with enzymescarbohydrates) with enzymes
– Transports undigested material to cell membrane for removalTransports undigested material to cell membrane for removal Location:Location: In the cytoplasm In the cytoplasm Composed of:Composed of: Digestive enzymes enclosed in a protective Digestive enzymes enclosed in a protective
membrane and a lipid bilayermembrane and a lipid bilayer Cell breaks down if lysosomes explode - this is how a Cell breaks down if lysosomes explode - this is how a
tadpole looses its tail when it turns into a frog!tadpole looses its tail when it turns into a frog!
Vacuoles (Plant and Vacuoles (Plant and Animal)Animal)
Job:Job: – Storage, Storage,
digestion, and digestion, and waste removalwaste removal
– Helps plants Helps plants maintain their maintain their shapeshape
Location:Location: – In the cytoplasmIn the cytoplasm
Composed of:Composed of: – Water & a thin Water & a thin
membranemembrane
Chloroplast (Plant)Chloroplast (Plant)
Job:Job: – Capture light energy Capture light energy
(in (in thylakoid thylakoid membranesmembranes) and ) and convert it into convert it into chemical energy chemical energy through through photosynthesisphotosynthesis..
Location:Location: – In the cytoplasm In the cytoplasm
Composed of:Composed of:– A double membraneA double membrane– GranaGrana – stacks of – stacks of
membranous sacsmembranous sacs
Cytoskeleton Cytoskeleton (Plant and Animal)(Plant and Animal)
Job:Job: – Support and structure (think tent poles!)Support and structure (think tent poles!)– Cell division and transportCell division and transport– Anchors organellesAnchors organelles
Location:Location: – In the cytoplasmIn the cytoplasm
Composed of:Composed of: – MicrotubulesMicrotubules: thin hollow cylinders made of protein: thin hollow cylinders made of protein– MicrofilamentsMicrofilaments: smaller, solid protein fibers: smaller, solid protein fibers
Let’s compare…Let’s compare…