USMLE Step 1 First Aid GÇô Microbiology Questions and answers (Rated A)

Bacterial Structures: Peptidoglycan - Gives rigid support, protects against osmotic pressure; Sugar backbone w/ cross-linked peptide side chains. (function; chemical composition) Bacterial Structures: Cell wall / cell membrane (G+'s) - Major surface Ag; Peptidoglycan for support. Teichoic acid induces TNF and IL-1. (function; chemical composition) Bacterial Structures: Outer membrane (G-) - Site of endotoxin (LPS), major surface Ag; Lipid A induces TNF and IL-1 Polysaccharide is the Ag (function; chemical composition) Bacterial Structures: Plasma membrane - Site of oxidative and transport enzymes; Lipoprotein bilayer (function; chemical composition) Bacterial Structures: Ribosome - Protein synthesis; 50S and 30S subunits (function; chemical composition) Bacterial Structures: Periplasm - Space btw the cytoplasmic membrane and the outer membrane in G- bacteria; Contains may hydrolytic enzymes, including beta-lactamases (function; chemical composition) Bacterial Structures: Capsule Function? Structure? (... and exception?) - Protects against phagocytosis; Polysaccharide (except in Bacillus anthracis , which contains D-glutamate) (function; chemical composition) Bacterial Structures: Pilus/fimbria - Mediate adherence of bacteria to cell surface, sex pilus forms attachment btw 2 bacteria during conjugation; Glycoprotein (function; chemical composition) Bacterial Structures: Flagellum - Motility; Protein (function; chemical composition)Bacterial Structures: Spore - Provides resistance to dehydration, heat, and chemicals; Keratin-like coat, dipiclonic acid (function; chemical composition) Bacterial Structures: Plasmid - Contains a variety of genes for ABX resistance, enzymes, toxins; DNA (function; chemical composition) Bacterial Structures: Glycocalyx - Mediates adherence to surfaces, especially foreign surfaces (e.g. indwelling catheters); Polysaccharide (function; chemical composition) Structures unique to gram (+) organisms - Teichoic acid Cell wall <img src="138b - cell wall.JPG" /> Structures common to Gram +/- organisms - Flagellum, pilus, capsule, PDG, cytoplasmic membrane <img src="138a - cell walls.JPG" /> Features unique to G(-) organisms - Endotoxin/LPS (outer membrane) Periplasmic space (location of many beta-lactamases) <img src="138c - cell wall gram neg.JPG" /> Bacteria w/ unusual cell membranes/walls - Mycoplasma: contain sterols and have no cell wall Mycobacteria: Contain mycolic acid. High lipid content. G(+) cocci - Staphylococcus Streptococcus G(-) cocci - Neisseria G(+) Rods - My cobacterium (acid-fast) List eria B acillus C lostridium C orynebacterium What happened when you were sending that email to Gram + Rod ? My List B ecame CC 'd My cobacterium (acid-fast) List eria B acillus C lostridium C orynebacterium What happened when you were sending that email to Gram + Rod ? My List B ecame CC 'd - G(+) RodsG(-) Rods - H ave Y ou E ver L istened to GNR (Guns n' Roses = Gram (-) Rods)? I like B oy B ands. B esides, Fran kly, I P refer Garden s to jungles. Haemophilus Yersinia Enterics (separate card) Legionella (silver stain) Bordatella Brucella Bartonella Francisella Pasteurella Gardnerella (gram variable)