BSC 160 1nd Edition Lecture 9Outline of Last Lecture 1. Antibiotics2. Gram+3. Gram –4. Cell Wall5. ArchaeaOutline of Current Lecture 1. Endospores2. Flagella3. Motility4. Pili & Fimbriae5. GlycocalyxCurrent LectureEndospores- Form of suspended animationResistant Cell Structures- Heat (>100*C)- Radiation (3x normal)- Chemicals (acids, bases, organics)- Desiccation (dehydration)- Can withstand UV lightSurface Structures- Found outside the cell1.) Flagella: Organs of motility- Bacterial flagella: rotate, spin- Sperm flagella: swim- Monotrichous: 1 flagellaThese 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.- Lophotichous: Multiple flagella emerging in small bunches from same sight- Peritrichous: Flagella dispersed all over cell’s surface.Flagellar Structure- Protein flagellin arranged in helix- Flagella attached thru hook & basal body [Gram (+), Gram (-)]Chemotaxis- Movement toward or away from chemical. Positive-toward, negative-awayPhototaxis- Movement toward or away from lights. Positive-toward, negative-awayAerotaxis- Bacteria that require oxygen can move toward higher concentration. Positive-toward, negative-awaySignal sets flagella into motion clockwise or counterclockwise- Counterclockwise movement- Run- Clockwise movement- TumbleGliding motility- Movement across a solid surface; Most of the time Gram (-)Mechanisms- Pili- Cast and reel-in- Surfactant- Changing property between surface & propelling bacteria forward- Motors- Proton gradientsAdvantages of Motility- Chemotaxis, phototaxis, aerotaxisPili and Fimbriae- External structures, bacteria use these for interacting- Pili or Pilus / Fimbriae or Fimbria- both made up of proteins- Pili- longer, less numerous. Holding Gram(-) microbes for DNA transfer- Fimbriae- shorter, more of them; bristle-likeGlycocalyx- Polysaccharide or protein material, covers outside of cell- Slime layer- loosely associated- Capsule- More tightly bound- Functions: Attachment, Protection of immune system, prevent desiccation, hold nutrients, create biofilms Quarumsensing. See other species and can change DNA. Hard to get rid ofStructural differences in Archaea and microbial
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