cell structure revised by bryant wong. cell theory all organisms are composed of one or more cells ...
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Cell StructureCell Structure
Revised by Bryant WongRevised by Bryant Wong
Cell TheoryCell Theory
All organisms are composed of one or All organisms are composed of one or more cellsmore cells
Cells are the smallest living thingsCells are the smallest living things Cells come from other cellsCells come from other cells
Does Size Really MatterDoes Size Really Matter
YesYes Surface area to volume ratioSurface area to volume ratio
Surface Area to Volume Video
MicroscopesMicroscopes
Resolution: the minimum distance two Resolution: the minimum distance two points can be apart and still be points can be apart and still be distinguished as two separate itemsdistinguished as two separate items
Light Microscope< Compound Light Microscope< Compound Microscope< Electron Microscope< Microscope< Electron Microscope< Scanning Electron Microscope Scanning Electron Microscope <Transmission Electron Microscope<Transmission Electron Microscope
Descriptions of Microscopes
What do all cells have?What do all cells have?
Centrally located genetic materialCentrally located genetic material CytoplasmCytoplasm Plasma membranePlasma membrane Chromosomes (carry genes)Chromosomes (carry genes) Ribosomes (make proteins)Ribosomes (make proteins) CytosolCytosol
Eukaryotic cells have internal Eukaryotic cells have internal membranes that compartmentalize their membranes that compartmentalize their functionsfunctions
The basic structural and functional unit of The basic structural and functional unit of every organism is one of two types of every organism is one of two types of cells: prokaryotic or eukaryoticcells: prokaryotic or eukaryotic
Only organisms of the domains Bacteria Only organisms of the domains Bacteria and Archaea consist of prokaryotic cellsand Archaea consist of prokaryotic cells
Protists, fungi, animals, and plants all Protists, fungi, animals, and plants all consist of eukaryotic cellsconsist of eukaryotic cells
Prokaryotic CellsProkaryotic Cells
Plant CellPlant Cell
Animal CellAnimal CellLE 6-9a
Flagellum
Centrosome
CYTOSKELETON
Microfilaments
Intermediate filaments
Microtubules
Peroxisome
Microvilli
ENDOPLASMIC RETICULUM (ER
Rough ER Smooth ER
MitochondrionLysosome
Golgi apparatus
Ribosomes:
Plasma membrane
Nuclear envelope
NUCLEUS
In animal cells but not plant cells: LysosomesCentriolesFlagella (in some plant sperm)
Nucleolus
Chromatin
Peptido…who?Peptido…who?
Archeabacteria lack peptidoglycanArcheabacteria lack peptidoglycan Gram Positive Vs Gram NegativeGram Positive Vs Gram Negative
Comparing Prokaryotic Comparing Prokaryotic and Eukaryotic Cellsand Eukaryotic Cells
Prokaryotic cellsProkaryotic cells Have no nucleusHave no nucleus DNA is in an unbound region called the DNA is in an unbound region called the
nucleoidnucleoid Lack membrane-bound organellesLack membrane-bound organelles
Comparing Prokaryotic Comparing Prokaryotic and Eukaryotic Cellsand Eukaryotic Cells
Eukaryotic CellsEukaryotic Cells Have DNA in a nucleus that is bounded by a Have DNA in a nucleus that is bounded by a
membranous nuclear envelopemembranous nuclear envelope Have membrane-bound organellesHave membrane-bound organelles Generally much larger than prokaryotic cellsGenerally much larger than prokaryotic cells The logistics of carrying out cellular The logistics of carrying out cellular
metabolism sets limits on the size of cellsmetabolism sets limits on the size of cells
EukaryotesEukaryotes
Archeabacteria seem to be more related Archeabacteria seem to be more related to eukaryotes than prokaryotes….what to eukaryotes than prokaryotes….what might this imply?might this imply?
The eukaryotic cell’s genetic The eukaryotic cell’s genetic instructions are housed in the nucleus instructions are housed in the nucleus and carried out by the ribosomesand carried out by the ribosomes
The nucleus contains most of the DNA in The nucleus contains most of the DNA in a eukaryotic cella eukaryotic cell
Ribosomes use the information from the Ribosomes use the information from the DNA to make proteinsDNA to make proteins
OrganellesOrganelles
Nucleus Ribosomes Organelles of the endomembrane system
The Nucleus: Genetic The Nucleus: Genetic Library of the CellLibrary of the Cell
The nucleus contains The nucleus contains most of the cell’s most of the cell’s genes and is usually genes and is usually the most conspicuous the most conspicuous organelleorganelle
The nuclear envelope The nuclear envelope encloses the nucleus, encloses the nucleus, separating it from the separating it from the cytoplasmcytoplasm
LE 6-10
Close-up of nuclearenvelope
Nucleus
Nucleolus
Chromatin
Nuclear envelope:Inner membraneOuter membrane
Nuclear pore
Porecomplex
Ribosome
Pore complexes (TEM) Nuclear lamina (TEM)
1 µm
Rough ER
Nucleus1 µm
0.25 µm
Surface of nuclear envelope
Ribosomes: Protein Ribosomes: Protein Factories in the CellFactories in the Cell
Ribosomes are particles Ribosomes are particles made of ribosomal RNA made of ribosomal RNA and proteinand protein
Ribosomes carry out Ribosomes carry out protein synthesis in two protein synthesis in two locations:locations: In the cytosol (free In the cytosol (free
ribosomes)ribosomes) On the outside of the On the outside of the
endoplasmic reticulum (ER) endoplasmic reticulum (ER) or the nuclear envelope or the nuclear envelope (bound ribosomes)(bound ribosomes)
LE 6-11
Ribosomes
0.5 µm
ER Cytosol
Endoplasmicreticulum (ER)
Free ribosomes
Bound ribosomes
Largesubunit
Smallsubunit
Diagram ofa ribosome
TEM showing ERand ribosomes
The endomembrane system regulates The endomembrane system regulates protein traffic and performs metabolic protein traffic and performs metabolic functions in the cellfunctions in the cell
Components of the endomembrane Components of the endomembrane system:system: Nuclear envelopeNuclear envelope Endoplasmic reticulumEndoplasmic reticulum Golgi apparatusGolgi apparatus LysosomesLysosomes VacuolesVacuoles MicrobodiesMicrobodies Plasma membranePlasma membrane
These components are either These components are either continuous or connected via transfer continuous or connected via transfer by vesiclesby vesicles
The endomembrane system is a The endomembrane system is a complex and dynamic player in the complex and dynamic player in the cell’s compartmental organizationcell’s compartmental organization
LE 6-16-3
Nuclear envelope
Nucleus
Rough ER
Smooth ER
Transport vesicle
cis Golgi
trans Golgi
Plasma membrane
The Endoplasmic Reticulum: The Endoplasmic Reticulum: Biosynthetic FactoryBiosynthetic Factory
The endoplasmic reticulum The endoplasmic reticulum (ER) accounts for more (ER) accounts for more than half of the total than half of the total membrane in many membrane in many eukaryotic cellseukaryotic cells
The ER membrane is The ER membrane is continuous with the nuclear continuous with the nuclear envelopeenvelope
The are two distinct regions The are two distinct regions of ER:of ER: Smooth ER, which lacks Smooth ER, which lacks
ribosomesribosomes Rough ER, with ribosomes Rough ER, with ribosomes
studding its surfacestudding its surface
LE 6-12
Ribosomes
Smooth ER
Rough ER
ER lumen
Cisternae
Transport vesicle
Smooth ER Rough ER
Transitional ER
200 nm
Nuclearenvelope
Smooth ERSmooth ER
FunctionsFunctions Synthesizes lipidsSynthesizes lipids Metabolizes carbohydratesMetabolizes carbohydrates Stores calciumStores calcium Detoxifies poisonDetoxifies poison
Rough ERRough ER
FunctionsFunctions Has bound ribosomesHas bound ribosomes Produces proteins and membranes, which Produces proteins and membranes, which
are distributed by transport vesiclesare distributed by transport vesicles Membrane factory for the cellMembrane factory for the cell
The Golgi Apparatus: The Golgi Apparatus: Shipping and Receiving Shipping and Receiving CenterCenter
The Golgi apparatus consists of The Golgi apparatus consists of flattened membranous sacs called flattened membranous sacs called cisternaecisternae
FunctionsFunctions Modifies products of the ERModifies products of the ER Manufactures certain macromoleculesManufactures certain macromolecules Sorts and packages materials into Sorts and packages materials into
transport vesiclestransport vesicles
LE 6-13
trans face(“shipping” side ofGolgi apparatus) TEM of Golgi apparatus
0.1 µm
Golgiapparatus
cis face(“receiving” side ofGolgi apparatus)
Vesicles coalesce toform new cis Golgi cisternaeVesicles also
transport certainproteins back to ER
Vesicles movefrom ER to Golgi
Vesicles transport specificproteins backward to newerGolgi cisternae
Cisternalmaturation:Golgi cisternaemove in a cis-to-transdirection
Vesicles form andleave Golgi, carryingspecific proteins toother locations or tothe plasma mem-brane for secretion
Cisternae
Lysosomes: Digestive Lysosomes: Digestive CompartmentsCompartments
A lysosome is a membranous sac of A lysosome is a membranous sac of hydrolytic enzymeshydrolytic enzymes
Lysosomal enzymes can hydrolyze Lysosomal enzymes can hydrolyze proteins, fats, polysaccharides, and proteins, fats, polysaccharides, and nucleic acidsnucleic acids
Lysosomes also use enzymes to recycle Lysosomes also use enzymes to recycle organelles and macromolecules, a organelles and macromolecules, a process called autophagyprocess called autophagy
LE 6-14a
Phagocytosis: lysosome digesting food
1 µm
Plasmamembrane
Food vacuole
Lysosome
Nucleus
Digestiveenzymes
Digestion
Lysosome
Lysosome containsactive hydrolyticenzymes
Food vacuolefuses withlysosome
Hydrolyticenzymes digestfood particles
LE 6-14b
Autophagy: lysosome breaking down damaged organelle
1 µm
Vesicle containingdamaged mitochondrion
Mitochondrionfragment
Lysosome containingtwo damaged organelles
Digestion
Lysosome
Lysosome fuses withvesicle containingdamaged organelle
Peroxisomefragment
Hydrolytic enzymesdigest organellecomponents
Vacuoles: Diverse Vacuoles: Diverse Maintenance CompartmentsMaintenance Compartments
Vesicles and Vesicles and vacuoles (larger vacuoles (larger versions of vacuoles) versions of vacuoles) are membrane-are membrane-bound sacs with bound sacs with varied functionsvaried functions
A plant cell or fungal A plant cell or fungal cell may have one or cell may have one or several vacuolesseveral vacuoles
LE 6-15
5 µm
Central vacuole
Cytosol
Tonoplast
Central vacuole
Nucleus
Cell wall
Chloroplast
VacuolesVacuoles
Food vacuoles are formed by Food vacuoles are formed by phagocytosisphagocytosis
Contractile vacuoles, found in many Contractile vacuoles, found in many freshwater protists, pump excess water freshwater protists, pump excess water out of cellsout of cells
Central vacuoles, found in many mature Central vacuoles, found in many mature plant cells, hold organic compounds and plant cells, hold organic compounds and waterwater
MicrobodiesMicrobodies
Enzyme bearing membrane enclosed Enzyme bearing membrane enclosed vesiclesvesicles Peroxisomes- catalyze the removal of Peroxisomes- catalyze the removal of
electrons associated with hydrogen atomselectrons associated with hydrogen atoms Glyoxysomes- in plants convert fats into Glyoxysomes- in plants convert fats into
carbohydratescarbohydrates
Mitochondria and Mitochondria and ChloroplastsChloroplasts Involved in energy Involved in energy
metabolismmetabolism Both contain their Both contain their
own DNA and own DNA and protein synthesis protein synthesis machinery…what machinery…what does this say?does this say?
Both surrounded by Both surrounded by a double a double membranemembrane
Arrived in the cells Arrived in the cells by endosymbiosisby endosymbiosis
MitochondriaMitochondria
Metabolize sugar to generate ATPMetabolize sugar to generate ATP
Crista
ChloroplastsChloroplasts
Use light to generate ATPUse light to generate ATP
Fibers of The Fibers of The CytoskeletonCytoskeleton
Microfilaments- 2 protein chains loosely Microfilaments- 2 protein chains loosely twinedtwined
Microtubules- largest- hollow tubesMicrotubules- largest- hollow tubes Intermediate filamentsIntermediate filaments
What is the function of What is the function of the cytoskeleton fibers?the cytoskeleton fibers? Modulate cell shapeModulate cell shape Permit cell movementPermit cell movement Move materials within the cytoplasmMove materials within the cytoplasm
Kineson moves towards the outside of the cellKineson moves towards the outside of the cell Dynein moves towards the inside of the cellDynein moves towards the inside of the cell
Extracellular Structures Extracellular Structures and Cell Movementand Cell Movement
Actin fillaments allow some cells to crawl, Actin fillaments allow some cells to crawl, forward movement achieved by myosinforward movement achieved by myosin
Cilia and Flagella- 9+2 structure (fundamental Cilia and Flagella- 9+2 structure (fundamental component of eukaryotic cells)component of eukaryotic cells)
Cell WallCell Wall Provide Protection Provide Protection
and Supportand Support Found in plants, Found in plants,
fungi and protistsfungi and protists Plants and protists Plants and protists
made of cellulosemade of cellulose Fungi made of Fungi made of
chitinchitin Primary walls, Primary walls,
middle lamella, middle lamella, some have some have secondary wallssecondary walls
Extracellular Matrix Extracellular Matrix (ECM)(ECM)
Animals lack cell walls Animals lack cell walls so they have ECM to so they have ECM to protect themprotect them GlycoproteinsGlycoproteins CollagenCollagen Elastin Elastin Fibronectin Fibronectin
IntegrinsIntegrins
Real Life ApplicationReal Life Application
Organelles keep the cell alive and the cells Organelles keep the cell alive and the cells keep organisms alive.keep organisms alive.
We inherit mitochondria from our mother.We inherit mitochondria from our mother. Organelle discoveries suggest that all cells had Organelle discoveries suggest that all cells had
a common ancestor. We all evolved from the a common ancestor. We all evolved from the same thing. Bacteria, eukaryotes, and archaea same thing. Bacteria, eukaryotes, and archaea all had a primitive organelle consisting of little all had a primitive organelle consisting of little polyphosphate. Researchers can track polyphosphate. Researchers can track evolutionary history.evolutionary history.
Relate surface area and volume with cell Relate surface area and volume with cell size and how it effects the cell.size and how it effects the cell.