Chapter 7- The Cell

Chapter 7- The CellStructure and FunctionLife is CellularSection 7-1

ProkaryotesEukaryotesMicroscopes- Early Pioneers1665 - Robert Hooke Observed a piece of cork with a compound microscopeSaw thousands of empty chambersCalled these chambers Cells1674 - Anton van LeeuwenhoekUsed a single lens microscope to look at pond waterRevealed thousands of tiny living organismsObservationsRobert Hookes CellsLeeuwenhoeks Organisms

Origins of the Cell Theory 1838- Matthias SchleidenAll plants are made of cells1839- Theodore SchwannAll animals are made of cells1855- Rudolph VirchowCells arise from other cellsThe Cell TheoryAll living things are composed of cellsCells are the basic units of structure and functions in living thingsNew cells are produced from preexisting cellsThe CellMost basic unit of lifeVarying sizes (.2 m -1000m)2 Common CharacteristicsSurrounded by a Cell MembraneContains DNA2 TypesProkaryotesEukaryotesProkaryotesBacteria & ArcheaPro- Before Karyon- NucleusGenetic information is NOT contained in nucleusCondensed in an area called the nucleoidSmaller and more simplistic.

EukaryotesEu- TrueKaryon- NucleusGenetic information is stored in the nucleusContains membrane bound organellesLarger and more complexPlants, animals, fungi, and protists

Prokaryote or Eukaryote?

Prokaryote or Eukaryote?

Prokaryote or Eukaryote?

Prokaryote or Eukaryote?

Prokaryote or Eukaryote?

Prokaryote or Eukaryote?

Light MicroscopyConfocal Light MicroscopyScans cell with laser beam and builds a 3D model of cells and partsHas its limits, light is diffracted as it passes through matter, limits the resolution of image. Almost impossible to see proteins or virusesElectron MicroscopesTransmission Electron MicroscopesBeams of electrons are shot through a thin slice of a specimenAllows detailed structures of small proteins to be seenScanning Electron MicroscopesBeam of electrons passes across specimenForms a highly detailed 3D image of the specimenMust be done in a vacuum to work properly Electron MicroscopesHas a resolution 1000X that of light microscopesWavelengths of electrons are much shorter than light2 Types:Transmission Electron MicroscopeScanning Electron MicroscopeNew Advances in MicroscopyScanning Probe MicroscopeTraces surface of specimen with a probeSo powerful it has observed a single atomCan operate in ordinary air (no special conditions needed)Used to image DNA and protein moleculesExamples of Microscopy

Eukaryotic Cell StructureSection 7-2Eukaryotic Cells IntroHighly complexOrganellesSpecialized structures within the cellDivides Cell into 2 SectionsNucleusCytoplasmThe CytoplasmPortion of the cell outside the nucleusHouses most organelles

The NucleusControl Center of the cellContains almost all the cells DNACoded with instructions for forming proteins and other important molecules

Nuclear EnvelopeCovers nucleusFilled with poresRegulates flow of material in and out of the nucleusRNA, Proteins, etc.

Chromatin & ChromosomesChromatinDNA bound to protein; normally spread throughout nucleusChromosomesCondensed chromatin that appears during cell divisionCarrier for genetic information through generations

Nucleolus Dense center of nucleusWhere ribosome assembly begins

RibosomesSmall particles of RNA and protein found in cytoplasmProduce proteins based on coded information from nucleus

Endoplasmic ReticulumSite where lipid components of cell membrane and protein assembly occurSmooth ERLipid synthesisRough ERCoated with RibosomesInvolved with protein assembly

Golgi ApparatusModifies, sorts, and packages proteins and other materials from the ER for storage or secretion outside cell

LysosomesSmall organelles filled with enzymes2 functionsDigestion of proteins, lipids, and carbohydrates for reuseBreaking down organelles that begun to shut down

VacuolesStorage structures that hold water, salts, proteins, and carbohydrates for future useCan be used in some simple cells as a pump to remove excess water

MitochondriaConvert the chemical energy stored in food into compounds that are more convenient for the cells useDouble membraneInner membrane is folded inside organelle

ChloroplastsCapture energy from the sunlight and convert it into chemical energy via photosynthesisContains chlorophyllMakes the structure green

CytoskeletonNetwork of protein filaments that helps the cell maintain its shape and deals with movement

Cytoskeleton SpecificsMircofilamentsMade of actin; creates flexible framework for cellMicrotubulesHollow tubes made of tubulins, forms spindle fibers during cell divisionCentriolesOrganize cell division; only in animal cellsThe Animal CellLacks a rigid cell wallSmaller Vacuole Contains CentriolesUsed during Cell Division

The Plant CellHas a rigid cell wallContains a very large vacuoleChloroplastsContains photosynthetic pigments

Labeling the Cell

Cell BoundariesSection 7-3