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  • ANTON VAN LEEUWNENHOEKOne of the first persons to use a microscope.Looked at pond water and saw small organisms.

  • ROBERT HOOKELooked at plant tissues in 1665.He specifically looked at cork.Looked like tiny chambers he called cells

  • THE CELL THEORY1. All living things are composed of cells.2. Cells are the basic unit of structure & function in living things.3. New cells are produced by existing cells.

  • Cells are the basic unit of life.Cells come in all different shapes & sizes.All living things are made up of cells!

  • Structures common to most cells1. cell membrane/cell wall2. nucleus3. cytoplasm

  • Biologist divide cells into one of two types:1. PROKARYOTE: do not contain a membrane bound nucleus(all bacteria are prokaryotes)2. EUKARYOTE: DO contain a membrane bound nucleus, and most have other specialized organelles.

  • Cell Size1. Cells are small because materials need to get into and out of the cell at a rate that will meet the cells needs.2. Surface area to volume ratio (Fig. 10-2 pg. 243)a. Larger surface area/volume ratio, the more materials a cell can exchangeb. As cell size increases, surface area to volume ratio decreases

  • Cell Size

  • CELL STRUCTURESWe are going to focus on eukaryotic cells and all their specialized organelles.ORGANELLES: literally means little organsThe cell is broken up into 2 regions:1. nucleus contains DNA2. cytoplasm portion of cell outside the nucleus; contains a variety of organelles; many substances are dissolved here

  • NUCLEUSFUNCTION: controls most of the cells processed & contains the DNA.Nuclear envelope selectively permeable; dotted with poresNucleolus site of ribosome productionContain CHROMATIN This is the granular material visible in the nucleus. They thicken & become CHROMOSOMES during cell division.

  • NUCLEOLUSDense structure INSIDE nucleus that make ribosomes!

  • NUCLEAR PORESHoles in the nuclear envelope that allow materials to pass between the nucleus and the cytoplasm.

  • RIBOSOMESSmall particles of RNA & protein found throughout the cytoplasm or attached to the endoplasmic reticulumMAIN FUNCTION: make proteins!

  • ENDOPLASMIC RETICULUMContinuous network of fluid filled canalsER is where proteins, lipid components of the cell membrane and other materials are synthesized

  • MORE ABOUT ERER can be one of 2 types:SMOOTH ER: no ribosomes/make lipids

    ROUGH ER: have ribosomes on the surface so it looks rough. Involved in the modification of proteins

  • GOLGI APPARATUSMAIN FUNCTION: Modify, sort & package proteins from the ER for storage or export

  • LYSOSOMESFilled with digestive enzymesMAIN FUNCTIONS:Digestion or breakdown of lipids, carbs, proteins, and worn out organelles so that they can be used by the rest of the cell.Found in white blood cells kill bacteriaFunction in developmental processes ( ex. digestion & absorption of tadpole tail)

  • VACUOLESMAIN FUNCTION: Storage!Much more obvious in plants. They are usually filled with water. This pressure makes it possible for a plant to support heavy structures like flowers.

  • MITOCHONDRIAMAIN FUNCTION:POWERHOUSE of the cell! Site of cellular respirationSome cells may have up to 800Contain own DNA & can reproduce themselvesMay have evolved from a prokaryotic ancestor that formed a symbiotic relationship with another prokaryotic cell

  • CHLOROPLASTSfound in plant cells and protists.MAIN FUNCTION:Capture energy from sunlight and convert it to chemical energy that the cell can use.(Like solar power plants.)Contain the green pigment CHLOROPHYLL

  • CYTOSKELETONMAIN FUNCTION:Protein filaments that have structural and locomotive functionsIncludes MICROTUBULES. They are long, hollow, cylindrical tubesExamples of microtubules include centrioles, cilia, and flagella

  • CYTOSKELETONIncludes MICROFILAMENTS. Long, solid, threadlike structures that give a structural frame- work to the cell.

  • CENTRIOLESCentrioles are specialized parts of the cytoskeleton that are involved in cell division.Plant cells DO NOT have centrioles.

  • Cilia & FlagellaCilia are short structures used to move substances along cell surfaces or to move cellsFlagella are long structures used to move cells

  • Cilia & Flagella


  • What are the parts?

  • Cell BoundriesCell membrane is selectively permeable & provides protection & supportSmall particles move more easily than large particlesNeutral molecules more easily than charged ionsNon polar more easily than polarSubstances that move across the cell membrane can vary from cell to cell, or the same cell from moment to momentMajor component of the cell membrane is a lipid bilayerProteins & carbohydrates are also found in the cell membrane

  • Cell membrane

  • Cell WallFound in plants, algae, fungi, and nearly all prokaryotes.MAIN FUNCTION: provide support & protection for the cellAnimal cells DO NOT have cell walls!

  • Maintaining HomeostasisAll cells must regulate what materials enter & leave; sometimes no energy is required to do this, other times energy is requiredPassive transport no energy is required to move substances from an area of high concentration to an area of low concentration

  • Types of Passive TransportDiffusion the movement of a solute from an area of high conc. To an area of low conc. Equilibrium is reached when an equal number of molecules move in both directions

  • Types of Passive TransportOsmosis the diffusion of water across a membrane from a region of high water concentration to a region of low water concentration

  • Types of Passive TransportFacilitated diffusion process by which transport proteins carry certain molecules across a membrane from high concentration to low concentration

  • Types of Osmotic SolutionsIsotonic solution solution has the same solute concentration as that of the living cell, there is no net movement of H2O

  • Types of Osmotic SolutionsHypertonic solution solution has a higher solute concentration than the inside of the cell; H2O moves out of the cell; animal cell will shrink (crenate); vacuole collapses in plant cells

  • Types of Osmotic SolutionsHypotonic solution solution has a lower solute concentration than the inside of the cell; H2O moves into the cell; animal cell will burst (lyse); plant cell will not (why?)

  • Types of Osmotic Solutions (animation of isotonic, hypertonic, hypotonic solutions)

  • Types of Osmotic Solutions

  • Active TransportEnergy is required to move substances from an area of low concentration to an area of high concentration; allows cells to have internal environments that are different chemically from the external environment

  • Types of Active TransportMolecular transport - proteins in the cell membrane work as pumps to move substances against the concentration gradient

  • Types of Active TransportEndocytosis - process by which a cell takes material into the cell by infolding of the cell membranePhagocytosis large particles taken inPinocytosis H2O or small particles are taken inExocytosis process by which cell releases large amounts of material; vacuole membrane fuses with the cell membrane

  • Types of Active Transport

  • Diversity of Cellular LifeUnicellular- one celled organismsBacterial, some protistsColony a group of unicellular organisms living togetherMulticellular - more than one cell; cells are specialized to perform a specific function

  • Diversity of Cellular LifeUnicellularMulticellular

  • Levels of Organization