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…