Cell Biology

Cell BiologyHistory Timeline1500s 1st LensesOriginally used to determine the quality of cloth1600s Telescope/microscope used a combination of lenses

History Timeline1665 Robert HookePublished drawings of cork using the 1st Light MicroscopeCoined the word cellCork cells looked like little rooms, which were called cells in his time

History Timeline1674 Anton van LeeuwenhoekUsed Microscopes to study natureStudied pond water

History Timeline1838 Matthias SchleidenPlants are made up of cells

History Timeline1839 Theodor SchwannAnimals are made up of cells

History Timeline1855 Rudolph VirchowStudied cell reproductionThis is where the Cell Theory came from.

Cell TheoryAll living things are composed of cellsCells are the basic units of structure and function in living thingsNew cells are produced from existing cells

Rudolph VirchowHistory Timeline1931 Janet PloweCell membrane is an actual structure not just space between two liquids

Basic Cell StructuresCell MembraneThin, flexibleSupport and protect cellALL cells!!!

Basic Cell StructuresCell WallStrong, RigidSupport and protect cell

Cell Wall (Continued)Plants, algae, fungi and almost all prokaryotesFound OUTSIDE the cell membraneAllows for water, oxygen, CO2 to pass throughConsists of Carbohydrates and proteinPlant cells = cellulose (tough carbohydrate fiber)Primary component of both wood and paper!!!

Basic Cell StructuresNucleus (Plural: Nuclei)BrainControls cell activitiesContains genetic material1st Discovered by Robert Brown 1831

Nucleus (Continued)Includes hereditary (genetic) informationDNA coded instructions for making proteinsChromatin granular and visible spread outChromosomes CONDENSED chromatin, ready for cell division

Basic Cell StructuresCytoplasmMaterial inside the cell (Does NOT include the nucleus)Other organelles found in the cytoplasmOrganelles = Little Organs

Different Types of Cells Prokaryotic Cells (Bacteria) Eukaryotic Cells(Animal and Plant)No NucleusGenerally Small/SimpleAll BacteriaMost have cell wallsHave a nucleusHave organelles (Little Organs)Only plant cells have cell walls.NucleolusSmall, dense region INSIDE the nucleusWhere the assembly of ribosomes beginRibosomes aide in the production of proteins.

Nuclear EnvelopeAlso known as the Nuclear membraneBilayer 2-layer membrane surrounding the nucleusPores 1000s of them! (little holes)RNA constantly going through

CytoskeletonBackbone to a humanFrame to a houseMatrix of Support Cyto = cell, skeleton = supporting structureHelps the cell maintain its shapeHelps move organelles within the cell.

MicrotubulesPart of the CytoskeletonHollow tubes of proteins (larger than microfilaments)Inside the cellServe as tracks for the organelles to move on.Like a roller coaster track that the car sits on and moves across.Outside the cellMovement of the cellCilia Small hair-like projectionsFlagellaLarge projection(s)

ParameciumE. Coli

SpermMicrofilamentsLong, thin fibers

RibosomesSmall and RoundMostly attached to Rough Endoplasmic ReticulumSome are found Free in the cell.Proteins assembled here using Code that comes from the nucleus.RNA (Ribonucleic Acid)

Endoplasmic Reticulum (ER)Components of the cell membrane are assembled here.Rough ERStudded with Ribosomes This is what gives it the Rough appearance.Some proteins are modified hereSmooth ERContains enzymes that do specific tasks.

Golgi ApparatusAttaches carbohydrates and lipids to proteinsThe proteins that come from the Rough ERLooks a lot like the Smooth ER

LysosomesGarbage Disposals, Pac-MansSmallFilled with enzymesBreak down lipids, carbohydrates and proteins from food Can be used by the rest of the cell.Break down organelles and debris that would just fill up the cell

VacuolesStorage unitsStore materialsPlants have one LARGE VacuolePressure for supporting heavy leaves/flowersEver seen a plant that hasnt been watered lately?Droopy/Wilted.Animals smaller form vessiclesTypically used for transporting substances in and out of the cell*we will learn more about these a little later in class.

ChloroplastsFound MOSTLY in plants Also found in some other organisms NOT animal or fungal cellsPhotosynthesis occurs hereConversion of sunlight into usable energy for the cell.

MitochondriaPowerhouse of the cellConvert food energy to high-power energy for use by the cellGrow, develop, moveFound in just about all Eukaryotic cellsie No bacteria!

Demonstration-What is the purpose of a cell membrane?Set-upIodine and WaterStarch and WaterIodine and StarchMembrane (baggie) with Twist tieWhat will happen?

Demonstration Conclusion

* Because of Diffusion, Iodine enters the bag.* The starch molecules are too big to leave the bag, but the iodine molecule are small enough to enter the bag* The iodine turns the starch in the bag a blue-black color (positive-test for starch)

Cell MembraneRegulates in/out of cellIn: Food and Water and . . .Out: Waste and. . .Lipid bilayer (bi = 2 , layer)Proteins that go through the layers Carbohydrates attached to the proteins on the outside of the cellThese are Markers it is how the cell is recognized.Can substances and water move through this membrane? What do you think?Terms:Solution: Liquid mixture of 2 or more substances Evenly mixedSolute: Item being dissolved into the liquid (solvent)Typically smaller amount than the solvent.Concentration: Amount of solutes in an amount (volume) of solution.Example: Salt WaterEverything wants to be equalDiffusionWorks the same way!Solutes move from an area of High Concentration to an area of low concentration until Equilibrium is reached.Equilibrium = EqualDoes NOT require energy!

If the substance (the solute) cant cross the membrane, then what?We say the membrane is not permeable to that substance (solute)

But. What happens? Nothing?Something?

OsmosisOsmosis: Diffusion of water across the membraneWater will move from the area of high concentration (of water) to the area of low concentration (of water) till equilibrium is reached. Requires No energy!Solution is Isotonic (Same Strength)

Hypertonic solutionHyper = More or AboveHyperactive = Lots of activity, extra energyMore solutes = More concentrated solution

If the environment outside of the cell is Hypertonic, what will happen? - Water flows out of cell - Cell shrinks.

Hypotonic solutionHypo = Less or BelowHypoglycemic = Low blood sugarLess solutes = Less concentrated solution

If the environment outside of the cell is Hypotonic, what will happen? - Water flows into the cell - Cell gets bigger.

Isotonic solutionIso = Same, EqualIsometric = Equal measurementsSame amount of solutes = Same concentrations

If the environment outside of the cell is Isotonic, what will happen? - Water flows into and out of the cell - The cell stays the same size

Osmotic PressurePressure exerted on a membrane by water

Most cells are Hypertonic (inside)So what would happen when the cell would come in contact with fresh water?

Just like this water balloon it will burst!So. . . .What about our blood?Our blood is Isotonic!

How do cell walls help a plant?Dont they come in contact with fresh water all the time?

Hyper Iso Hypo

So, what are the solutions outside the cell?A.) Hypertonic (Outside the cell)B.) Hypotonic (Outside the cell)Review(Occurring across the Lipid Bilayer)DiffusionMovement of solutes across a membraneRequires No EnergyOsmosisMovement of water across a membraneRequires No EnergyHypertonicHigh amount of Solutes (High Concentration of Solutes)HypotonicLow amount of Solutes (Low Concentration of Solutes)IsotonicEqual amounts of Solutes (at Equilibrium)Facilitated DiffusionItems that can not move across the membrane (lipid bilayer) can use SPECIALIZED channels to move across the membraneExamples: Glucose, sugars, salts, ionsSpecific Proteins are the Specialized channels.Fast, SpecificResponds to concentrationsMove from an area of high concentration to an area of low concentration.Requires NO energy!

Active TransportMovement of items against concentrationsMove from an area of low concentration to an area of high concentration.Uses ENERGY!!!!Compare to a pumpNa+ out, K+ in Inside the cell, low Na+, and high K+

More Ways to Move materials:ExocytosisRemoval of substances from the cell by vesicles that then fuse with the cell membrane to release items from the cell.

EndocytosisTaking materials in by creating vesicles around them.

Two Types of Endocytosis:Phagocytosis clumps of food, large molecules, whole cells that need to be broken down by the cellPhago = devour, cyto = cell, osis = process ofRequires lots of energy!Pinocytosis small particles/fluids, already broken down molecules

ReviewCytoCellExoOutEndoInOsisProcess of PhagoDevour

Unicellular OrganismOne CelledThey grow, respond, reproduceExample: YeastBoth Prokaryotes and EukaryotesProkaryote: BacteriaEukaryote: Algae and Yeast (fungi)

ParamesiumProtists

Multicellular OrganismMany CellsInterdependent cellsEach has a specialized function that depends on anotherExample: Football or Baseball teamEach player dependent on another player to do their jobMove, react, respond, produce substancesExample: HumansWe have nerve cells, muscle cells, blood cells, skin (epithelial) cells, pancreatic cells (enzymes that digest food)

Levels of OrganizationCellsBasicDivision of labor (Specialization)TissuesGroup of similar cells, perform a specific functionMuscle tissue, nerve tissue, epithelial (skin) tissue, connective tissue (bone, blood, cartilage, lymph)OrgansGroups of tissues working togetherExample: A Muscle has nerve and connective tissue running through the muscle tissuesOrgan SystemsGroup of organs that work together to do/complete a specific task11 Major groups (Page 892)