Step 1 First Aid – Microbiology Final Examination With 100% Accurate Solutions Edition.

Step 1 First Aid – Microbiology Final
Examination With 100% Accurate
Solutions 2025-2026 Edition.
Bacterial Structures: Peptidoglycan - Answer 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) - Answer Major surface Ag;
Peptidoglycan for support. Teichoic acid induces TNF and IL-1. (function; chemical composition)



Bacterial Structures: Outer membrane (G-) - Answer 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 - Answer Site of oxidative and transport enzymes;
Lipoprotein bilayer (function; chemical composition)



Bacterial Structures: Ribosome - Answer Protein synthesis; 50S and 30S subunits (function;
chemical composition)



Bacterial Structures: Periplasm - Answer 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?) - Answer Protects
against phagocytosis; Polysaccharide (except in Bacillus anthracis , which contains D-glutamate)
(function; chemical composition)



Bacterial Structures: Pilus/fimbria - Answer Mediate adherence of bacteria to cell surface,
sex pilus forms attachment btw 2 bacteria during conjugation; Glycoprotein (function; chemical
composition)



Bacterial Structures: Flagellum - Answer Motility; Protein (function; chemical composition)



Bacterial Structures: Spore - Answer Provides resistance to dehydration, heat, and chemicals;
Keratin-like coat, dipiclonic acid (function; chemical composition)

,Bacterial Structures: Glycocalyx - Answer Mediates adherence to surfaces, especially foreign
surfaces (e.g. indwelling catheters); Polysaccharide (function; chemical composition)



Structures unique to gram (+) organisms - Answer Teichoic acid Cell wall <img src="138b -
cell wall.JPG" />



Structures common to Gram +/- organisms - Answer Flagellum, pilus, capsule, PDG,
cytoplasmic membrane <img src="138a - cell walls.JPG" />



Features unique to G(-) organisms - Answer 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 - Answer Mycoplasma: contain sterols and have
no cell wall Mycobacteria: Contain mycolic acid. High lipid content.



G(+) cocci - Answer Staphylococcus Streptococcus



G(-) cocci - Answer Neisseria



G(+) Rods - Answer 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 - Answer G(+)
Rods



G(-) Rods - Answer 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)



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) -
Answer G(-) Rods

,Pleomorphic (G-) bacteria - Answer Rickettsiae Chlamydiae (Giemsa stain)



Rickettsiae Chlamydiae (Giemsa stain) - Answer Pleomorphic (G-) bacteria



Spirochetes (G-) - Answer Leptospira Borrelia (Giemsa stain) Treponema



Leptospira Borrelia (Giemsa stain) Treponema - Answer Spirochetes (G-)



Neither G+ nor G- (b/c no cell wall) - Answer Mycoplasma



Bugs that won't Gram stain - Answer These Rascals May Microscopically Lack Color
Treponema (too thin to be visualized) Rickettsia (intracellular parasite) Mycobacteria (high-lipid-
content cell wall requires acid-fast stain) Mycoplasma (no cell wall) Legionella pneumophilia
(primarily intracellular) Chlamydia (intracellular parasite; lacks muramic acid cell wall)



Visualizing Treponemes - Answer Darkfield microscopy and fluorescent Ab staining



Visualizing Mycobacteria - Answer Acid-fast stain



Visualizing Legionella - Answer Silver stain



Giemsa's stain is used to visualize...? - Answer use for: Borrelia Plasmodium Trypanosomes
Chlamydia



PAS (periodic acid-Schiff) stain - Answer stains glycogen, mucopolysaccharides*; Used to
diagnose Whipple's dz (*PASs the sugar)



Ziehl-Neelsen stain - Answer Use to stain Acid-fast bacteria



India ink - Answer used to visualize Cryptococcus neoformans



Silver stain - Answer used to visualize: fungi, Legionella

, Chocolate agar w/ factors V (NAD) and X (hematin) - Answer H. influenzae



Media/Special culture requirements for: N. gonorrheae - Answer Thayer-Martin media
(Chocolate agar based, w/ various ABX) (Media used for isolation)



Thayer-Martin media (Chocolate agar based, w/ various ABX) - Answer N. gonorrheae



Media/Special culture requirements for: B. pertussis - Answer Bordet-Gengou (potato) agar
(Media used for isolation)



Bordet-Gengou (potato) agar - Answer B. pertussis



Media/Special culture requirements for: C. diphtheriae - Answer Tellurite plate, Loffler's
media (Media used for isolation)



Tellurite plate, Loffler's media - Answer C. diphtheriae



Media/Special culture requirements for: M. tuberculosis - Answer Lowenstein-Jensen agar
(Media used for isolation)



Lowenstein-Jensen agar - Answer M. tuberculosis



Media/Special culture requirements for: M. pneumoniae - Answer Eaton's agar (Media used
for isolation)



Eaton's agar - Answer M. pneumoniae



Media/Special culture requirements for: E. coli - Answer Eosin-methylene Blue (EMB) agar
(blue-black colonies w/ metallic sheen) (Media used for isolation)



Eosin-methylene Blue (EMB) agar (blue-black colonies w/ metallic sheen) - Answer E. coli



Media/Special culture requirements for: Lactose-fermenting enterics - Answer Pink colonies