MICR J210 1st Edition Lecture 2 Outline of Last Lecture I. The Early Years of MicrobiologyA. Antoni LeeuwenhoekB. Carolus LinnaeusII. The Golden Age of MicrobiologyA. Fracesco RediB. Louis PasteurC. The Scientific MethodD. Ignaz SemmelweissE. Robert KochIII. The Modern Age of MicrobiologyA. Serology IV. Four Categories of Human PathogensA. Bacteria B. FungiC. ProtozoaD. VirusesOutline of Current Lecture I. Eukaryotes and ProkaryotesA. What is the difference between the two?II. Structural Differences between Eukaryotes and ProkaryotesIII. Chromosomal DifferencesIV. Differences in LocomotionV. Bacterial NomenclatureVI. Cell Walls and CapsulesCurrent LectureEukaryotes and Prokaryotes- Eukaryotes: diploid cells (contain 2 copies of DNA) and have a true nucleus- Prokaryotes: haploid cells (contain 1 copy of DNA)o Composed of bacteria primarily as well as archaea - Pathogens can come from bacteria and eukaryotes but never archaea- Phylogenic TreeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Archaea Similar to bacteria but live in very harsh environments (hot springs, soils, and salt lakes, etc.)o Bacteria (can be both beneficial and harmful to humans)o Eukaryotes Have a true nucleus with a nuclear membrane Can also be pathogenic (i.e. protozoa or parasitic worms)- Other facts to know:o Bacteria do not undergo meiosis because they reproduce asexuallyo Membranous organelles are absent in ALL prokaryoteso The cell membrane of bacteria “acts” as the membrane of mitochondria allowing ATP to be produced Structure Differences between Eukaryotes and Prokaryotes- Structure of an animal cello True nucleus and membranous organelles Millions of base pairs tightly coiled around histoneso No cell wall- Structure of a plant cello Cell wall made of cellulose o (In bacteria—the cell wall is made of peptidoglycan)- Structure of Prokaryotic cellso Single chromosome is arranged as a circle with both end bound together Only 5,000 base pairs that freely float in cytoplasm Cannot sexually reproduceo Pili (fimbriae) Appendages that attach to surfaces that act as anchoring devices Do NOT cause locomotiono Cell wall composed of peptidoglycan Because they do not have a cytoskeleton, bacteria derive their shape and form from the cell wallo There are no membrane-bound organelles so everything floats in the cytoplasmfreelyLocomotion- Cilia: composed of microtubules and are smaller than flagella); short hair-like structures used to move particles across cell surfaceo ONLY found in eukaryotes Example: cilia on parameciumo Motion in is one plane (beating)o Common in the mucosa membranes in humans such as the respiratory tract- Flagella: long whip-like structure used for movemento Both in prokaryotes and eukaryoteso Motion in prokaryotes is rotation (spins around in axis: like a propeller)o Motion in eukaryotes is undulation (moves back and forth in one plane: like a windshield wiper)o Used for locomotion Direction is determined by phototaxis and Chemotaxis- Phototaxis: movement towards a source of lighto Accomplished by a photosynthesizing cell- Chemotoxis: movement towards a chemical source (usually food)o Flagella in Eukaryotes Example: Sperm The cell membrane coats the entire flagella (no true penetration of the flagella into the cell because the cell membrane is continuous) Can only exist on one pole of the cell Undulation Made of Microtubules and are fundamentally larger than the flagella found in bacteriao Flagella in Prokaryotes Flagella are embedded in cell envelope (penetrates membrane) Several possible configurations:- Monotrichous: only one flagella- Lophotrichous: multiple flagella on the same pole - Amphitrichous: flagella on opposite ends (bipolar)- Peritrichous: flagella on multiple poles It is important to know if the bacteria is motile or nonmotile, because this will effect what treatment will be chosen to kill the bacteria Composed of flagellin- Flagellin differs between species of bacteria Three parts to the flagella- Basal apparatus: disk shaped structure that runs at ATP o Responsible for the actual mechanics of the flagella- Hooko Responsible for the angle of the flagella- Filamento Composed of flagellin (subunits of protein)o Special Flagella Axial filaments: flagellum built into the structure of bacteria that operates like a corkscrew to allow for burrowing of the bacteria into other structures- Found in bacterial spirochetes- Cell corkscrews to move- Pseudopodso Extensions of the cytoskeleton Common in white blood cellso Follow Chemotaxis Cytokines (chemicals) attract immune cells to the site of infection for phagocytosis- Side notes about ribosomeso Prokaryotic ribosomes are smaller and more simple than eukaryotic one and are usually the target for many antibioticso Prokaryotic ribosomes lack a scaffold for incoming tRNA- Order of how to tell the difference between a Eukaryote and a Prokaryoteo First, look at the nucleus if there is oneo Second, look at organelleso Third, look and ribosomeso Fourth, look at chromosomeso Lastly, look at the size  Eukaryotes are much bigger than prokaryotesNomenclature- Bacillus: RODo Rod or cylinder-shaped- Coccus: SPHEREo Circular or sphere-shaped- Spirochete: SPIRALo Spiral-shaped in order to perform “corkscrew” motion- Aggregations of bacteriao Strep—CHAINo Dip—PAIRo Staph—CLUSTERCell Membrane and Cell Wall- Functions of bacterial cell membraneo Diffusion: No ATP used Passive (freely flowing) Facilitated (requires helper protein—NO energy used)o Active Transport: ATP usedo Energy production via the electron transport systemo Mobility Serves as a base for bacterial flagella within the cell membrane- Side noteso Water moves toward the area of a higher salt solutiono Permease: only allows certain types to enter the cello Diffusion moves from an area of high concentration to low concentration- Bacterial Cell Wallo Gram positive: stains positive Thicker cell wallo Gram negative: stains negative Thin cell wall Contains Type 2 Fimbriae- Pili (Fimbriae)o NOT used for locomotiono Type 1: used to attach to other tissues like an anchoro Type 2: only in Gram negative  Used for genetic exchange (conjugation)o Pili are virulence factors Pili determine whether or not the bacteria is capable of staying, colonizing, and causing disease Use