Chapter 4-Chapter 4-A View of the CellA View of the Cell

4.1-The Discovery of Cells4.1-The Discovery of Cells

Cells are the basic units of living Cells are the basic units of living organismsorganisms

Development of the microscope allowed Development of the microscope allowed scientists to view cellsscientists to view cells

Cell TheoryCell Theory 1665-Robert Hooke1665-Robert Hooke

Uses compound microscope to observe Uses compound microscope to observe corkcork

Hollow boxes…..CELLS!!Hollow boxes…..CELLS!!

1830s-Schleiden and Schwann1830s-Schleiden and Schwann Schleiden-all plants are composed of Schleiden-all plants are composed of

cells!cells! Schwann-all animals are composed of Schwann-all animals are composed of

cells!cells!

Three Parts of Cell TheoryThree Parts of Cell Theory

1. All organisms composed of one or more 1. All organisms composed of one or more cells.cells.

2. Cell is the basic unit of organization of 2. Cell is the basic unit of organization of organisms.organisms.

3. All cells come from preexisting cells.3. All cells come from preexisting cells.

History of the MicroscopeHistory of the Microscope 1665-Hooke’s Microscope1665-Hooke’s Microscope

Three lensesThree lenses Poor QualityPoor Quality Little detailLittle detail

1700-Anton van Leeuwenhoek1700-Anton van Leeuwenhoek Built over 240 microscopes!Built over 240 microscopes! Single LensSingle Lens Better QualityBetter Quality Observed red blood cells & bacteriaObserved red blood cells & bacteria

Mid 1800s-Compound Light MicroscopeMid 1800s-Compound Light Microscope Series of lensesSeries of lenses Light passes through object then lensLight passes through object then lens More detailMore detail

1940s-Electron Microscopes1940s-Electron Microscopes Beam of electrons through magnetic fieldBeam of electrons through magnetic field Specimen in vacuumSpecimen in vacuum Only view dead cells or organismsOnly view dead cells or organisms

1.SEM-Scanning Electron Microscope1.SEM-Scanning Electron Microscope Surface of specimen-3D Picture!Surface of specimen-3D Picture!

2.TEM-Transmission Electron Microscope2.TEM-Transmission Electron Microscope Through the specimenThrough the specimen Magnify 100s or 1,000s of times!Magnify 100s or 1,000s of times!

3.STM-Scanning Tunneling Microscope3.STM-Scanning Tunneling Microscope Arrangement of atoms on surfaceArrangement of atoms on surface Map hills and valleysMap hills and valleys

Basic Cell Types…Basic Cell Types…

Look at internal organization!Look at internal organization!

Prokaryotes-lacks internal structuresProkaryotes-lacks internal structures

Eukaryotes-membrane bound, Eukaryotes-membrane bound, internal structures.internal structures. Structures called organellesStructures called organelles Largest organelle = NUCLEUS!Largest organelle = NUCLEUS!

Section 4.2-Eukaryotic Cell Section 4.2-Eukaryotic Cell StructureStructure

Must have boundaries!Must have boundaries!

Plasma MembranePlasma Membrane Boundary between cell & environmentBoundary between cell & environment FlexibilityFlexibility Controls movement of materialsControls movement of materials

Cell Wall-only plant cells!Cell Wall-only plant cells! Rigid, surrounds membraneRigid, surrounds membrane Thicker, stronger network for structural Thicker, stronger network for structural

supportsupport

Fluid-Mosaic MembraneFluid-Mosaic Membrane

GET UNDER CONTROL!!!!GET UNDER CONTROL!!!!

Nucleus-contains cell’s DNA, manages Nucleus-contains cell’s DNA, manages cell functioncell function

Surrounded by nuclear envelopeSurrounded by nuclear envelope Double membrane-pores allow movementDouble membrane-pores allow movement

Chromatin-long strands of DNAChromatin-long strands of DNA Packed into chromosomesPacked into chromosomes

NucleusNucleus

NucleolusNucleolus Region inside nucleusRegion inside nucleus Produces particles for protein synthesisProduces particles for protein synthesis

Particles are called ribosomesParticles are called ribosomes Cell assembles enzymes according to Cell assembles enzymes according to

DNADNA Not bound by membraneNot bound by membrane

NucleolusNucleolus

Assembly, Transport, & Assembly, Transport, & StorageStorage

Cytoplasm-outside nucleus, surrounds Cytoplasm-outside nucleus, surrounds organellesorganelles Clear liquidClear liquid Important chemical reactions (protein Important chemical reactions (protein

assembly) take place hereassembly) take place here

Endoplasmic Reticulum (ER)-Endoplasmic Reticulum (ER)- Network of interconnected compartmentsNetwork of interconnected compartments Surface folded into cellSurface folded into cell

Tissues in a box!Tissues in a box! Site for lipid synthesis in cellSite for lipid synthesis in cell

Smooth or Rough?Smooth or Rough?

Smooth ERSmooth ER Lacks ribosomes on surfaceLacks ribosomes on surface

Rough ERRough ER Studded with ribosomes on surfaceStudded with ribosomes on surface

ER acts as cell’s delivery system!ER acts as cell’s delivery system!

Structures for StorageStructures for Storage Golgi ApparatusGolgi Apparatus

Closely stacked, flattened membrane sacsClosely stacked, flattened membrane sacs Receives proteins and lipidsReceives proteins and lipids Modifies them chemically, repackagesModifies them chemically, repackages Distributes them throughout membraneDistributes them throughout membrane

Vacuole-sac of fluidVacuole-sac of fluid Temporary storage of food, enzymes etc.Temporary storage of food, enzymes etc. Animal cell-small and numerousAnimal cell-small and numerous Plant cell-single large vacuole for waterPlant cell-single large vacuole for water

Reduce, Reuse, RECYCLE!Reduce, Reuse, RECYCLE!

LysosomesLysosomes Digest excess or worn out cell parts, Digest excess or worn out cell parts,

food particles, and invading food particles, and invading viruses/bacteriaviruses/bacteria

Membrane protects digestive enzymes Membrane protects digestive enzymes from rest of cellfrom rest of cell

Energy TransformersEnergy Transformers MitochondriaMitochondria

Break down food-convert to energy!Break down food-convert to energy! Peanut-shapedPeanut-shaped Highly folded inner membrane for more Highly folded inner membrane for more

energy storageenergy storage

Chloroplasts-plants only!Chloroplasts-plants only! Transform light energy into chemical energyTransform light energy into chemical energy Chlorophyll-traps energy from sunChlorophyll-traps energy from sun

Green color!Green color!

NRG!!NRG!!

Support and LocomotionSupport and Locomotion CytoplasmCytoplasm

1. Cytoskeleton-network of fibrous elements1. Cytoskeleton-network of fibrous elementsAct as scaffold for organelle supportAct as scaffold for organelle support

2. Microtubules-thin, hollow cylinders2. Microtubules-thin, hollow cylindersMade of proteinMade of protein

3. Microfilaments-thin, solid fibers3. Microfilaments-thin, solid fibersBoth make up most of cytoskeletonBoth make up most of cytoskeleton

LET’S GET MOVING!LET’S GET MOVING!

CiliaCilia Short, numerous hair-like projectionsShort, numerous hair-like projections On cell’s surfaceOn cell’s surface Movement like “the wave!”Movement like “the wave!”

FlagellaFlagella Longer projectionsLonger projections Whip-like motionWhip-like motion One or two per cellOne or two per cell

Flagella vs CiliaFlagella vs Cilia

Cellular OrganizationCellular Organization 1. Single-celled organisms: 1. Single-celled organisms:

UnicellularUnicellular 2. Many-celled organisms: 2. Many-celled organisms:

MulticellularMulticellular 3. Cells functioning together for 3. Cells functioning together for

activity: Tissuesactivity: Tissues 4. Two or more tissues functioning 4. Two or more tissues functioning

together: Organstogether: Organs 5. Organs working together to carry 5. Organs working together to carry

out major life functions:Organ Systemout major life functions:Organ System