Cell BiologySylvia T. Pratiwi

Section 1: Introduction to the Cell

Introduction to Cell BiologyWHAT is cell biology

WHY study cell biology?

Properties of cells

Prokaryotic & Eukaryotic cell types

Model organisms

Hierarchy of Biological Order

Properties of CellsSmallest membrane-bound unit capable of independent functioning ; smallest unit considered alive; nuclei, ribosomes aren't alive, but cells are.they are highly complex and organized Cells Possess a Genetic Program and know how to use itall cells can reproduce- one becoming two. Simple (binary fission) in prokaryotes, much more complex-mitosis in eukaryotes.Cells acquire and use energy: (Chemo) Heterotrophs, (photo)autotrophs, chemoautotrophsChemical reactions are constantly taking place in the cell. Catabolism break down molecules into smaller units to release energyAnabolism construct molecules from smaller units, require energyMetabolism the total of both

Properties of cellsLots of mechanical activity in cells also- movement of cells, movement of things within cells.

Cells respond to external stimuli- illness, losing blood, eating, etc. can be described cellularly

Cells Evolve (that is, current cells appear to be the ancestors of past cells)

Discovery of CellsThe invention of the lens

Robert Hooke (1665): observed a thin slice of cork (dead plant cells) with a microscope. He described what he observed as little boxes (cells).

Discovery of CellsAntonie van Leeuwenhoek (1675): was the first person to observe living cells.

Sizes of Living Things10 m1 m0.1 m1 cm1 mm100 nm10 nm1 nm0.1 nmmousefrog egghuman eggmost bacteriavirusproteinatomantelectron microscopelight microscopehuman eyehumanblue whalechloroplastrose1 km100 m100m10m1mplant and animal cellsaminoacidostricheggCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

MicroscopesMagnification: refers to the microscopes power to increase an objects apparent size

Resolution: refers to the microscopes power to show detail clearly

Microscopy Today: Compound Light MicroscopeLight passed through specimenFocused by glass lensesImage formed on human retinaMax magnification about 1000XResolves objects separated by 0.2 mm, 500X better than human eye

Light Microscope

Light MicroscopeElodea - Aquatic Plant

Microscopy Today: Transmission Electron MicroscopeAbbreviated T.E.M.Electrons passed through specimenFocused by magnetic lensesImage formed on fluorescent screenSimilar to TV screenImage is then photographedMax magnification 1000,000sXResolves objects separated by 0.00002 mm, 100,000X better than human eye

Transmission Electron Microscope (TEM)

Transmission Electron Microscope (TEM)Herpes VirusPlant Root Cell

Microscopy Today: Scanning Electron MicroscopeAbbreviated S.E.M.Specimen sprayed with thin coat of metal goldElectron beam scanned across surface of specimenMetal emits secondary electronsEmitted electrons focused by magnetic lensesImage formed on fluorescent screenSimilar to TV screenImage is then photographed

Scanning Electron Microscope (SEM)

Scanning Electron Microscope (SEM)

Scanning Electron Microscope (SEM)Mosquito Head

Scanning Electron Microscope (SEM)Fly Eye

Scanning Electron Microscope (SEM)

Scanning Electron Microscope (SEM)PollenYeastRed Blood Cell, Platelet, and White Blood Cell

TEM vs. SEMViruses leaving a cell

Microscopy Today: Confocal MicroscopyNarrow laser beam scanned across transparent specimenBeam is focused at a very thin planeAllows microscopist to optically section a specimenSections made at different levelsAllows assembly of 3d image on computer screen that can be rotated

Microscopy and Amoeba proteuseyeamoeba, light micrographamoeba, scanning electron micrographlight raysocular lensobjective lensspecimencondenser lenslight sourcea. Compound light microscopeelectron gunelectron beamscanning coilspecimenc. Scanning electron microscopeelectron sourceelectron beamb.Transmission electron microscopespecimen85m200 nm500mpseudopod segment, transmission electronmicrographelectromagneticcondenserlensesfinalCondenserlenssecondary electronsobservation screenor photographic plateelectromagneticobjective lenselectromagnetic condenser lenselectromagnetic projector lenselectron detectorTVViewingscreenCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

The Cell TheoryWho developed the cell theory?Matthias Schleiden (1838): concluded that all plants are composed of cells

Theodor Schwann (1839): concluded that all animals are composed of cells

Rudolph Virchow (1855): determined that cells come only from other cells

The Cell TheoryWhat is the cell theory?1.All living things are composed of one or more cells.2.Cells are organisms basic units of structure and function.3.Cells come only from preexisting cells

Cell DiversitySizeShapeInternal Organization

Cell Diversity- Size

Cell Diversity- Size15.24 cm long, 12.7 cm wide, 1.3 kgsSmallest Cells:Longest Cells:Ostrich EggBiggest Cells:

Cell SizeCells range in size from one millimeter down to one micrometer

Cells need a large surface area of plasma membrane to adequately exchange materials.

The surfaceareatovolume ratio requires that cells be small

Volume is living cytoplasm, which demands nutrients and produces wastesCells specialized in absorption utilize membrane modifications such as microvilli to greatly increase surface area per unit volume

Surface to Volume RatioOne 4-cm cube96 cm2192 cm2384 cm264 cm364 cm364 cm31.5:13:16:1Eight 2-cm cubesSixty-four 1-cm cubesTotal surface area (height width number of sides number of cubes)Total volume (height width length number of cubes)Surface area: Volume per cube (surface area volume)Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Cell Diversity- ShapeCells differ widely in shape.Most cells are roughly cuboidal or spherical.

Cell Diversity- Internal OrganizationNucleus: contains DNA which directs the activity of the cell

Organelle: a cell component that performs specific functions in the cell

Eukaryotes: cells that contain a nucleus and membrane-bound organelles

Prokaryotes: cells that lack nuclei and membrane-bound organelles

Characteristics of All CellsA surrounding membraneProtoplasm cell contents in thick fluidOrganelles structures for cell functionControl center with DNA

Eukaryotes vs. ProkaryotesEukaryotes (animals, plants, fungi, protists) and prokaryotes (bacteria) differ greatly in structure.

Prokaryotic CellsFirst cell type on earthCell type of Bacteria and Archaea

Prokaryotic CellsNo membrane bound nucleusNucleoid = region of DNA concentrationOrganelles not bound by membranes

Eukaryotic CellsNucleus bound by membraneInclude fungi, protists, plant, and animal cellsPossess many organellesProtozoan

Representative Animal Cell

Representative Plant Cell

Sheet1

ProkaryotesEukaryotes

nucleus?NO (nucleoid)YES

membrane-bound organelles?NOYES (Many)

size1 - 10 mm10 - 50 mm

when evolved?3.5 billion years ago1.5 billion years ago

cytoplasm?YESYES

cell membrane?YESYES

cell wall?Some DoPlants

ribosomes?YESYES

DNA?CircularFree FloatingChromosomes in Nucleus

examplesBacteriaPlants, Animals, Fungi, and Protists

THE END!

Referenceshttp://learn.genetics.utah.edu/content/cells/organelles/

http://www.tutorvista.com/biology/microscope-parts-and-functions

http://materialcerdas.wordpress.com/teori-dasar/transmission-electron-microscopy-tem/

http://www.researchgate.net/post/What_is_the_difference_between_SEM_and_TEM_techniques2

http://www.diffen.com/difference/Eukaryotic_Cell_vs_Prokaryotic_Cell

sylvia.pratiwi@gmail.com

sylvia_pratiwi@ugm.ac.id

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