The CellThe Cell

All Living things are composed of All Living things are composed of cellscells All Cells have/contain the following:All Cells have/contain the following: Cell Membrane - Lipid BilayerCell Membrane - Lipid Bilayer - Separates inside from outside - Separates inside from outside

CytoplasmCytoplasm CytoplasmCytoplasm - everything but - everything but

DNA/NucleusDNA/Nucleus

Two Cell typesTwo Cell types

        ProkaryoticProkaryotic Cells Cells 1.1.            Primitive cells – include bacteriaPrimitive cells – include bacteria 2.2.          No nucleusNo nucleus

3.3.          No Membrane-bound organellesNo Membrane-bound organelles

4.4.          Very Small 1-10 micrometersVery Small 1-10 micrometers

5.5.          Single Strand of Circular “naked” DNASingle Strand of Circular “naked” DNA

6.6.          Contain Contain RibosomesRibosomes

Typical Prokaryotic Typical Prokaryotic CellCell

EukaryoticEukaryotic CellsCells

EukaryoticEukaryotic Cells Cells

1.1. 1.1.            Contain a Contain a NucleusNucleus which protects DNA / which protects DNA / ChromosomesChromosomes

2.2. 2.2.          Much larger than prokaryotic cellsMuch larger than prokaryotic cells

3.3. 3.3.          Have many different types of Have many different types of Membrane boundMembrane bound organellesorganelles - - compartmentalization = efficiencycompartmentalization = efficiency

Eukaryotic CellsEukaryotic Cells

Animal Animal Eukaryotic CellEukaryotic Cell

Plant Eukaryotic Plant Eukaryotic CellCell

OrganellesOrganelles

Membrane-Bound organelles only Membrane-Bound organelles only found in found in EukaryotesEukaryotes

Localize Chemical Reactions Localize Chemical Reactions making the cell far more efficientmaking the cell far more efficient

Major Organelles of the Eukaryotic CellMajor Organelles of the Eukaryotic Cell

The The NucleusNucleus ““eukaryotic” means “true eukaryotic” means “true

nucleus”nucleus” Contains & protects the Contains & protects the

cell’s DNAcell’s DNA Helps coordinate the Helps coordinate the

division of cellsdivision of cells Surrounded by a Surrounded by a Nuclear Nuclear

EnvelopeEnvelope Envelope is double Envelope is double

layered with layered with an an Inner & Inner & Outer membraneOuter membrane

Has perforations called Has perforations called Nuclear PoresNuclear Pores which which allow large molecules to allow large molecules to pass in/out of the nucleuspass in/out of the nucleus

Contains a Contains a NucleolusNucleolus RibosomesRibosomes are made in are made in

this regionthis region Contains DNA packaged in Contains DNA packaged in

structures called structures called chromosomeschromosomes ChromosomChromosom

eses

MitochondrMitochondriaia

Serves as the Serves as the “powerhouse “powerhouse of the cell” by of the cell” by generating generating chemical chemical energyenergy Has it’s own Has it’s own

DNA*DNA* Can divide on Can divide on

its own*its own*

Chloroplasts (Plant Cell Only)Chloroplasts (Plant Cell Only) Is the “cell’s farm” - Is the “cell’s farm” -

meaning food is meaning food is generated here.generated here.

Does this by Does this by photosynthesisphotosynthesis - - the conversion of the conversion of COCO22, H, H22O and O and

sunlight into sugarsunlight into sugar Contain Contain

ChlorophyllChlorophyll - a - a green pigment - green pigment - which does thiswhich does this

Has it’s own DNA*Has it’s own DNA* Can divide on its Can divide on its

own*own*

Ribosomes

Are NOT Are NOT membrane-bound & membrane-bound & also exist in also exist in prokaryotesprokaryotes

Are used to Are used to manufacture manufacture proteinsproteins

Granular in Granular in appearanceappearance

Often found on Often found on “rough” “rough” endoplasmic endoplasmic reticulumreticulum**

Endoplasmic ReticulumEndoplasmic Reticulum Are folds of Are folds of

membranes used to membranes used to package & modify package & modify proteins made by proteins made by ribosomes. They ribosomes. They also make lipidsalso make lipids

2 types2 types ““RoughRough” - which ” - which

is usually near is usually near nucleus and nucleus and covered with covered with ribosomes giving ribosomes giving it its “rough” it its “rough” appearance. appearance. (Finishes proteins)(Finishes proteins)

““SmoothSmooth” - which ” - which is usually away is usually away from the nucleus from the nucleus (produce lipids)(produce lipids)

Examples of Endoplasmic Examples of Endoplasmic ReticulumReticulum

Smooth ERSmooth ER Rough ERRough ER

Golgi Golgi BodiesBodies

Are the post offices of Are the post offices of the cellthe cell

Modify (address) Modify (address) proteins & lipids and proteins & lipids and send them in send them in packages (packages (vessiclesvessicles) ) throughout (or out of) throughout (or out of) the cell.the cell.

LysosomesLysosomes Small Vessicles

which serve to digest particles and clean-up cells

Contain Lysozyme – a powerful digestive enzyme

Digests food particles

Destroys worn-out organelles

Self-Destructs worn-out cells

CentriolesCentrioles(Animal Cell (Animal Cell Only)Only)

Serve as Serve as construction/organization construction/organization points for cellular points for cellular microtubulesmicrotubules

Organize and transfer Organize and transfer chromosomes and other chromosomes and other organelles during Meiosis & organelles during Meiosis & MitosisMitosis

Occur in some prokaryotes, Occur in some prokaryotes, protists & animals. Do not protists & animals. Do not occur with fungi and plantsoccur with fungi and plants

Tube like structures usually Tube like structures usually at right angles to each at right angles to each other.other.

Some animals have Some animals have centriole-like structures at centriole-like structures at the base of flagella called the base of flagella called basal bodiesbasal bodies..

TonoplastTonoplast(water vacuole)(water vacuole)(plant cells only)(plant cells only)

Large HLarge H22O / Lipid / O / Lipid /

waste storage tankwaste storage tank Provides pressure Provides pressure

((Turgor pressureTurgor pressure) to ) to maintain cell maintain cell structurestructure

Cell WallCell Wall Provides support / Provides support /

protection for protection for plant cellplant cell

Two layers of cell Two layers of cell wallwall Primary Cell Primary Cell

WallWall – Outer – – Outer – CelluloseCellulose only only

Secondary Cell Secondary Cell WallWall – Inner – – Inner – Cellulose & Cellulose & LigninLignin

Cell membrane is Cell membrane is innermost layerinnermost layer

CytoskeletonCytoskeleton Network of fibers Network of fibers

which help organize which help organize the internal the internal arrangement within arrangement within cells.cells.

Three basic types of Three basic types of fibers compose fibers compose cytoskeleton:cytoskeleton: Actin FilamentsActin Filaments

• Thinnest fibers ~7nMThinnest fibers ~7nM• Formed from protein Formed from protein

ActinActin MicrotubulesMicrotubules

• Largest component Largest component of cytoskeleton ~25 of cytoskeleton ~25 nMnM

• Formed from protein Formed from protein TubulinTubulin

Intermediate Intermediate filamentsfilaments

• Intermediate in size Intermediate in size and can varyand can vary

• Form from several Form from several proteins inluding proteins inluding vimentinvimentin & & keratinkeratin