Cell Structure & Cell Structure & FunctionFunction

Robert Hooke-1665 Coined the word “cell” Looked at cork cells

Robert Brown -1831 Discovered the "nucleus"

Theodor Schwann - 1838 Cells are unit of biological structure

Mattias Schleiden – ca. 1850 Cells are the fundamental basis of life

Virchow -1858 All cells come from cells

1. Every living organism is made up of at least one cell.

2. Cells are the basic structural and functional units of mulicultural organisms.

3. All cells arise from preexisting cells.

100 m

10 m

1 m

10 cm

1 cm

1 mm

100 m

10 m

1 m

100 nm

10 nm

1 nm

0.1 nm

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Eukaryotic CellsEukaryotic Cells

MitochondrionMitochondrion

VirusVirus

ProteinsProteins

AtomsAtoms

Prokaryotic: Smaller, 1—5 µm No organelles No nucleus DNA in circular loop

Eukaryotic: Larger, 8—100 µm Membranous organelles Nucleus DNA in linear chromosomes

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All cells possess a plasma membrane, cytoplasm, genetic material

Plasma membrane has phospholipid bilayer, embedded glycoproteins

Isolates cytoplasm from environment Regulates molecular movement into and

out of cell Interacts with other cells/environment

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Genetic material - DNA, found in the nucleus

Cytoplasm Cytosol (the fluid part)

Water Salts Organic monomers and polymers

Organelles

AnimalAnimalCellCell

AnimalAnimalCellCell

PlantPlantCellCell

PlantPlantCellCell

NucleusNucleus

GolgiGolgi

MitochondriaMitochondria

EndoplasmicEndoplasmicReticulumReticulum

CentriolesCentrioles ChloroplastsChloroplasts

AnimalAnimalCellCell

AnimalAnimalCellCell

PlantPlantCellCell

PlantPlantCellCell

NucleolusNucleolus

RibosomesRibosomes

Central VacuoleCentral Vacuole

Smooth E.R.Smooth E.R. Cell WallCell Wall

Protein fibers Give Cell shape; networks of intermediate

filaments Help Cell movement; microfilaments &

microtubules Amoeboid movement Muscle contraction Cell migration during development

Organelle movement & suspension Cyclosis; pathways for vesicle migration

Cell division

MicrotubuleMicrotubule

MicrofilamentsMicrofilaments

IntermediateIntermediateFilamentsFilaments

Actin subunitsActin subunits

Tubulin subunitsTubulin subunits

EndoplasmicReticulum

Mitochondrion

PlasmaMembrane

Tubular extensions of plasma membrane

Movement of fluid, or locomotion Two functionally different types

Cilia: numerous, paddle-like, synchronized Flagella: longer, fewer, more whip-like

Filled with microtubules 9 pairs in periphery; 2 singlets in center “9+2” arrangement (for eukaryotes)

““Sheath” Sheath” X.S.X.S.

CellCellMembraneMembrane

ShaftShaft

BaseBase(a Centriole)(a Centriole)

T.E.M.

T.E.M.

Paramecium

X.S.X.S.

11112222

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4444

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Shaft,Shaft,x.s.x.s. Microtubule Microtubule DoubletsDoublets

Cell MembraneCell Membrane

Dynein ArmsDynein Arms

Central Central SingletsSinglets

Microtubule Microtubule TripletsTriplets

Basal BodyBasal BodyBasal Body,Basal Body,

x.s.x.s.

Scanning E.M.Scanning E.M.of sperm on eggof sperm on eggScanning E.M.Scanning E.M.

of sperm on eggof sperm on egg

Corkscrew Movement(Pulls)

Whipping Movement(Pushes)

Water Water

Power Stroke Recovery StrokeWater

Scanning E.M.Scanning E.M.of a ciliateof a ciliate

Cell control and genetics Seen Genes in thread-like chromosomes Control production of all proteins

Bounded by nuclear envelope Made up of Double lipid bilayer Pores regulate transport

Not always at center of cell

NucleolusNucleolus

PoresPores

Chromatin ThreadsChromatin Threads(Chromosomes)(Chromosomes) NuclearNuclear

EnvelopeEnvelope

Chromatin – DNA not coiled up into a chromosome

Chromosome – DNA coils around proteins called histones to create linear chromosomes

Contains nucleolus of RNA Site of ribosome assembly

PlasmaPlasmaMembraneMembrane

NucleusNucleus

NuclearNuclearPoresPores

NucleoliNucleoli

NucleusNucleus

Cell WallCell Wall

ChromosomesChromosomes

-made of RNA and protein

- Site of protein synthesis

- Dark granules, (usually drawn as small circles)

Folded membranes attached to nucleus

Rough ER - protein synthesis

Ribosomes chain amino acids into polypeptide

Ribosomes on outside surface of rough ER

Composed of rRNA and proteins

Smooth ER

Lipid synthesis

RibosomesRibosomes

UnitUnitMembraneMembrane

VesiclesVesiclesformingforming

Rough ERRough ERRough ERRough ER

Smooth ERSmooth ERSmooth ERSmooth ER

RibosomesRibosomes

Processes material synthesized by ER Packages material and provides “address

label” Distributes material in sacs called vesicles Some for inside, others outside cell Secretory vesicles merge with cell

membrane Synthesis and transport of

polysaccharides

Material Material ReceivedReceivedFrom ERFrom ER

Material DestinedMaterial Destinedfor Exportfor Export

TEMTEM

Produced by Golgi apparatus

Vesicles containing hydrolytic enzymes

Digestive system of cell

Digest material engulfed by cell

Digest and recycle damaged organelles

LysosomeLysosome

Destined forDestined forExportExport

GolgiGolgiEndoplasmicEndoplasmic

ReticulumReticulum

Destined forDestined forGolgiGolgi

Special kidney-like organelle

Draws water in from cytoplasm & expels it

Important for some single-celled freshwater animals

Requires ATP

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Paramecium sp.

Expelling WaterExpelling Waterto Outsideto Outside

ExpandedExpandedwith Waterwith Water

Large, water-filled spaces (cell sap)

Can take up over 90% of cell volume

Surrounded by tonoplast (single membrane)

Functions: Storage of pigments (red/blue), acids,

salts, wastes

Maintain cell pressure (turgor pressure)

VacuoleVacuole(tonoplast)(tonoplast) Cell WallCell Wall

Cyt

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Cyt

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NormalNormalPlant CellPlant Cell

In SaltIn SaltWaterWater

Space between Cell WallSpace between Cell Walland Cell Membraneand Cell Membrane

Normal

In Salt Water

“Powerhouse” of cell Numerous Glucose catabolism Bounded by double membrane Matrix / cristae Have their own DNA and ribosomes;

self-replicating

CristaeCristaeMatrixMatrix

OuterOuterMembraneMembrane

InnerInnerMembraneMembrane

Green plants only Captures light energy Produces carbohydrate from CO2 and H2O

In cytoplasm of mostly mesophyll cells of leaf

Stroma / grana (thylakoid stacks) Have their own DNA and ribosomes; self-

replicating

ThylakoidsThylakoids

OuterOuterMembraneMembrane

InnerInnerMembraneMembrane

One GranumOne Granum

StromaStroma

Associated w/photosynthesis

Double bilipid membrane

Many functions

Chloroplasts

Storage of pigments

Storage of photosynthetic products

DoubleDoubleBilipidBilipid

MembraneMembrane

StarchStarchGranulesGranules

CapsuleCapsule

Cell WallCell WallPlasmaPlasmaMembraneMembrane

CytosolCytosol

Nucleoid DNANucleoid DNA

FlagellumFlagellum

Plasmid DNAPlasmid DNA

Small (<5 mircometers)

Cytosol, DNA, ribosomes, cell membrane, (usually a cell wall too)

Nucleoid – location of chromosome

Single, circular chromosome

Plasmid – small DNA ring, separate from nucleoid

Flagella with a 9+0 structure (never cillia)

Capsule/slime layer – polysaccharide coatings for protection

Pili – protein jutting out from cell wall

The endThe endThe endThe end