Biol 209 1st Edition Lecture 4 Outline of Last Lecture I. Functions of Carbs and ProteinsII. Prokaryotic Structuresa. Cell membraneb. Cell wallIII. Gram StainingOutline of Current Lecture I. Non Typical Cell WallsII. Gram Staining ProcessIII. Prokaryotic Outer Cell StructureCurrent LectureI. Non Typical Cell Wallsa. Myobacteriuam have a unique mycolic acid containing wall. It’s very hydrophobic and provides resilience and virulence. It serves as the basis for identifying and treating myobacterial infection. II. Gram Staining Processa. Acid Fast stain: carbolfusion dye is used to stain Myobacterium species. Dye binds mycolic acid and is retained despite acid wash. b. Grams Stain: crystal violet dye. Gram + cells retain the dye after washing because they have many layers of peptidoglycan.c. Gram Staining Process:i. Crystal Violet (primary dye)1. Both positive and negative cells walls stain with dyeii. Grams Iodine (mordant)1. (+): Dye crystals trapped in wall2. (-): No effect of iodineiii. Alcohol (decolorize)1. (+): Crystal remain in wall2. (-): Outer membrane weakened cell loses dyeThese 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.iv. Safranin (Red dye counterstain)1. (+): Red dye has no effect2. (-): Red dye stain the colorless cellIII. Prokaryotic Outer Cell Structuresa. Flagella provide mobility. One or many flagella may be present, they can have a polar location. b. Flagella structure: Filament, hook, basal body. i. Energy provided by proton flow into the cell. This is used to rotate the flagellac. Type of movement depends upon the direction of flagellai. Counterclockwise: smooth swimming (running)ii. Clockwise: tumbling1. Alternate running and tumbling leads to a “random walk.” Running moves the cell forward, tumbling results in a change of direction. The choice of direction is random. 2. Chemotaxis: a biased random walka. Receptors bound by attractants prolong CCW rotation of flagella (running). The higher the attractant concentration,the longer the time spent in run mode. This results in movement toward the area of highest attractant