How long have there How long have there been cells?been cells?

•Bacteria evolved about 3 billion years ago.

• Can be just a simple membrane filled with DNA.

What allowed us to see What allowed us to see cells?cells?

The MicroscopeThe Microscope Robert HookeRobert Hooke

CellsCells

The basic unit of life. The basic unit of life. The building blocks of all living thingsThe building blocks of all living things

The Cell TheoryThe Cell Theory

All living things are made of cells.All living things are made of cells.

Cells come from other cells (Cell Division).Cells come from other cells (Cell Division).

Cells are the smallest working units of living Cells are the smallest working units of living things. things.

Levels of OrganizationLevels of Organization

Smallest is a cellSmallest is a cell

tissuetissue

organorgan

Organ systemOrgan system

Largest is an organismLargest is an organism

ProkaryotesProkaryotes

A prokaryotic cell has A prokaryotic cell has no “true nucleus” and no “true nucleus” and lack membrane lack membrane bound organelles.bound organelles.

Still make proteins and Still make proteins and have DNAhave DNA

EukaryotesEukaryotes

Eukaryotes have a nucleus and also Eukaryotes have a nucleus and also have all of the membrane bound have all of the membrane bound organelles.organelles.

Plant CellPlant CellKey Feature?

Tough, rigid

CELL WALL

Animal CellAnimal Cell

CytoplasmCytoplasm

Cytoplasm

CytoplasmCytoplasm

The “juice” of the cell.The “juice” of the cell. The “right” The “right”

environment for the environment for the chemical reactions of chemical reactions of the cell.the cell.

Lipid BilayersLipid Bilayers

Cell Membrane

Cell Membrane, a lipid Cell Membrane, a lipid bilayerbilayer

The barrier between the cell and the environment.The barrier between the cell and the environment. Controls what gets in and out of a cell.Controls what gets in and out of a cell. Building different Building different membranesmembranes is one way different cell is one way different cell

types are made.types are made.

Plant CellPlant Cell

Cell Wall

Cell WallCell Wall

Made of cellulose.Made of cellulose. Serves to give a firm Serves to give a firm

structure to plantsstructure to plants

Can’t poop? Eat Can’t poop? Eat more fiber (cellulose)more fiber (cellulose)

Nuclear MembraneNuclear Membrane

Membrane around Membrane around nucleus. nucleus.

Carefully controls Carefully controls what gets in and out.what gets in and out.

Protects DNA!Protects DNA!

NucleusNucleus

Nucleus

NucleusNucleus

Membrane Bound*Membrane Bound* Contains DNA (the Contains DNA (the

genetic instructions genetic instructions that make you… that make you… you). you).

Nucleolus Nucleolus (Be careful to spell (Be careful to spell correctly)correctly)

Ribosomes (RNA and Ribosomes (RNA and proteins) assembled proteins) assembled herehere

Endoplasmic Reticulum Endoplasmic Reticulum (ER)(ER)

ER

Endoplasmic Reticulum, Endoplasmic Reticulum, the ERthe ER

Membrane Bound*Membrane Bound* Smooth ER makes Smooth ER makes

lipids. lipids. (For Membranes)(For Membranes)

Rough ER Rough ER ((ribosomesribosomes)) makes proteins.makes proteins.

Sends proteins to Sends proteins to Golgi.Golgi.

Golgi Body (Golgi Stack)Golgi Body (Golgi Stack)

Golgi

Golgi BodyGolgi Body Sorts proteins. Sorts proteins. Sent to:Sent to:

Secreted (released Secreted (released from cell)from cell)

Plasma MembranePlasma Membrane Membrane bound Membrane bound

organelles.organelles.

Pancreas?

Secretes INSULIN.

Not working? Diabetes.

LysosomeLysosome

Lysosome

Lysosomes and Lysosomes and peroxisomesperoxisomes

Membrane Bound*Membrane Bound* Store or destroy Store or destroy

waste.waste. Lysosomes are Lysosomes are

acidic, like your acidic, like your stomach.stomach.

Secretory PathwaySecretory Pathway Proteins are coded for Proteins are coded for

by by DNADNAmade on made on rough ERrough ER by by ribosomesribosomessent to sent to GolgiGolgi for sorting for sortinggo go to to LysosomeLysosome NucleusNucleus Cell MembraneCell Membrane or or releaserelease out of cell. out of cell.

VacuoleVacuole

Vacuole

VacuoleVacuole

Large in plants.Large in plants. Stores water Stores water

ChloroplastsChloroplasts

Chloroplast

ChloroplastsChloroplasts

Membrane Bound*Membrane Bound* Sunlight energy is Sunlight energy is

converted to sugar.converted to sugar. Filled with Filled with

chlorophyll, making chlorophyll, making plants GREEN!plants GREEN!

MitochondriaMitochondria

Mitochondria

MitochondriaMitochondria

Membrane Bound* Membrane Bound* (double membrane)(double membrane)

Sugar is BURNED, Sugar is BURNED, making ATP making ATP (Energy).(Energy).

PLANTS and PLANTS and ANIMALS get their ANIMALS get their ENERGY HERE!!ENERGY HERE!!

CentriolesCentrioles

Centrioles

CentriolesCentrioles

During Cell Division During Cell Division separate separate chromosomes into chromosomes into the daughter cells.the daughter cells.

Plants organize their Plants organize their spindles, but lack spindles, but lack centrioles.centrioles.

CytoskeletonCytoskeleton

Cytoskeleton

CytoskeletonCytoskeleton

Supports the cell:Supports the cell: ActinActin MicrotubulesMicrotubules

Molecules are also Molecules are also transported through transported through the cytosol along the cytosol along these skeletal these skeletal “tracks” with tiny “tracks” with tiny motors.motors.

ChromosomesChromosomes

DNA, instructions for DNA, instructions for making proteinsmaking proteins

Proteins manage the Proteins manage the chemical reactions chemical reactions that are YOU!that are YOU!

Plant or Animal Cell?

RibosomesRibosomes

Make proteinsMake proteins In cytoplasm or In cytoplasm or

studding the surface studding the surface of the rough ER.of the rough ER.

Plant Cells Animal Plant Cells Animal CellsCells

ChloroplastsChloroplasts CentriolesCentrioles

Cell WallCell Wall

Larger VacuoleLarger Vacuole

Composition of Cell Composition of Cell MembraneMembrane

Proteins

Carbohydrates

Phosphate heads

Lipid tails

Phospholipid Bilayer

DiffusionDiffusion

Movement of molecules from a high concentration to a low concentration

When molecules spread out to an even concentration

Concentration GradientConcentration Gradient

Concentration difference on two sides of Concentration difference on two sides of a barriera barrier

High

Low

EquilibriumEquilibrium

An even concentration on both sides of An even concentration on both sides of the membranethe membrane

ExamplesExamples

PerfumePerfume GasGas Dye in waterDye in water

Ultimately the molecules want to create a Ultimately the molecules want to create a balance or EQUILIBRIUMbalance or EQUILIBRIUM

Try ThisTry This

In a diffusion situation:In a diffusion situation:

OsmosisOsmosis

Movement of water from a high to a low Movement of water from a high to a low concentration, in an attempt to even out a concentration, in an attempt to even out a concentration gradient of solute particles.concentration gradient of solute particles.

ExamplesExamples

Water in a damWater in a dam WaterfallsWaterfalls

Wants to create an EQUILIBRIUMWants to create an EQUILIBRIUM

Solve:Solve:

10 % Iodine90% H2O

100 % Water

5 % Iodine95% H2O

95 % H2O5% Iodine

PlasmolysisPlasmolysis

A special case involving osmosis and A special case involving osmosis and plantsplants

When water is drawn out of the cell When water is drawn out of the cell causing the cell membrane to shrink.causing the cell membrane to shrink.

Selectively PermeableSelectively Permeablehttp://http://

www.indiana.edu/www.indiana.edu/~p~p

hys215/lecture/hys215/lecture/lecnotes/lecnotes/lecgraphics/lecgraphics/diffusion2.gifdiffusion2.gif

Passive transport – takes NO Passive transport – takes NO energy. (like flowing energy. (like flowing downhill)downhill)

Only works from High to Low Only works from High to Low concentrations!concentrations!

Channels – only let certain things throughChannels – only let certain things through

Active transport – Takes Active transport – Takes energy! (like walking energy! (like walking uphill)uphill)

proteins- Use energy (ATP) to move proteins- Use energy (ATP) to move substancessubstances

channels – May transport two molecules channels – May transport two molecules one is being concentrated while other is one is being concentrated while other is diffusing (flowing from High to Low)diffusing (flowing from High to Low)

http://www.biologie.uni-hamburg.de/b-online/library/biolohttp://www.biologie.uni-hamburg.de/b-online/library/biology107/bi107vc/fa99/terry/images/ATPpumA.gifgy107/bi107vc/fa99/terry/images/ATPpumA.gif

Endocytosis (UPTAKE)Endocytosis (UPTAKE)

A “bubble” of membrane pinches off A “bubble” of membrane pinches off Moving large particles INTO the cell.Moving large particles INTO the cell.

Exocytosis (secretion) – Exocytosis (secretion) – think opposite of think opposite of endocytosis (like EXIT)endocytosis (like EXIT) A “bubble” of membrane fuses with the cell A “bubble” of membrane fuses with the cell

membranemembrane Large particles move OUT of the cellLarge particles move OUT of the cell..

Inside Outside

Phagocytosis - like Phagocytosis - like endocytosis but with very endocytosis but with very large particles (bacteria)large particles (bacteria)

http://gak.med.kagawa-u.ac.jp/~daigin/eng_info/Hisology_&_Cell_Biology/PIC2.jpghttp://gak.med.kagawa-u.ac.jp/~daigin/eng_info/Hisology_&_Cell_Biology/PIC2.jpg

Red Blood Cells being “eaten” by a disease fighting White Blood Cell

TissuesTissues

What makes skin and muscle cells What makes skin and muscle cells different?different?

Skin and muscle cells make different Skin and muscle cells make different proteins, allowing different jobs to be proteins, allowing different jobs to be done!done!

What makes cells What makes cells different?different?

Even though each cell has all your DNA, Even though each cell has all your DNA, different parts are “read” and used in different parts are “read” and used in different cellsdifferent cells..

This is called gene “expression” or gene This is called gene “expression” or gene useuse

Muscle Tissue (myocytes)Muscle Tissue (myocytes)

Cell Job: MovementCell Job: Movement Cell parts: cytoskeleton, myosin, and Cell parts: cytoskeleton, myosin, and

ATP (energy)ATP (energy) Many cells fuse to form one long cell, Many cells fuse to form one long cell,

with many nucleiwith many nuclei Actin, Myosin and other proteins burn Actin, Myosin and other proteins burn

ATP to allow movement.ATP to allow movement.

Myosin walks on Actin Myosin walks on Actin “tracks”“tracks”

http://www.sci.sdsu.edu/movies/actin.gifhttp://www.sci.sdsu.edu/movies/actin.gif

Muscle Fibers shortenMuscle Fibers shorten

Nervous Tissue (neurons)Nervous Tissue (neurons)

Cell Job: Relay messages through the Cell Job: Relay messages through the bodybody

Cell Parts needed: Cell Parts needed: various channels to relay “electrical” signalvarious channels to relay “electrical” signal Chemicals to send message cell to cell Chemicals to send message cell to cell

(neurotransmitters like dopamine, GABA, (neurotransmitters like dopamine, GABA, serotonin, acetylcholine)serotonin, acetylcholine)

http://en.wikipedia.org/wiki/Image:SynapseIllustration.png

Intestinal Tissue Intestinal Tissue (epithelial cells)(epithelial cells)

Cell Job: to absorb nutrientsCell Job: to absorb nutrients Cell Parts: Cell Parts:

Channels to let nutrients into cellChannels to let nutrients into cell Channels to pump nutrients into blood Channels to pump nutrients into blood

streamstream

Concentrating nutrients Concentrating nutrients in bloodin blood

Eyes (Retinal Tissue)Eyes (Retinal Tissue)

Cell Job: to sense lightCell Job: to sense light Cell Parts: various proteins that react to Cell Parts: various proteins that react to

light and others to deliver the message to light and others to deliver the message to the optic nervethe optic nerve

Rod cells in eye sense black and whiteRod cells in eye sense black and white Cones sense colorsCones sense colors