Microbiology Lab Midterm Barbosa
EMB (eosin methylene blue) agar - ✔️✔️selective and differential, inhibits growth of
gram-positive and permits the differentiation of gram negative intestinal pathogens
based on lactose fermentation (E. coli-dark center metallic green, E. aerogenes-mucoid
and large, S. enterditis)
MAC (MacConkey's) agar - ✔️✔️selective and differential, crystal violet and bile salts
to inhibit gram positive, those that can ferment lactose acidically appear red, negative
appears colorless; determined by neutral red (S. enteriditis, E. coli)
Advantages of Solid Media - ✔️✔️allows for isolation of bacteria as pure culture; mixed
bacteria can be separated
microbial metabolism - ✔️✔️the means by which a microorganism obtains the energy
and nutrients it needs to live and reproduce
agar - ✔️✔️bacteriologically inert
semisolid media - ✔️✔️useful for the cultivation of microaerophilic bacteria or
determination of bacterial motility
all purpose media - ✔️✔️TSA (tryptic soy agar) and TSB (tryptic soy broth)
turbid - ✔️✔️diffusion uniform throughout the broth
sediment - ✔️✔️settles at the bottom
pellicle - ✔️✔️flocculent growth, some may float to the top
endospores - ✔️✔️not readily killed by many antimicrobial treatments (may be central,
terminal, or subterminal)
germination - ✔️✔️not a reproductive process, but a process of differentiation
gram stain - ✔️✔️1. crystal violet
2. iodine mordant
3. ethanol decolorizer
4. safranin counterstain
example of gram positive bacteria - ✔️✔️M. luteus
EMB (eosin methylene blue) agar - ✔️✔️selective and differential, inhibits growth of
gram-positive and permits the differentiation of gram negative intestinal pathogens
based on lactose fermentation (E. coli-dark center metallic green, E. aerogenes-mucoid
and large, S. enterditis)
MAC (MacConkey's) agar - ✔️✔️selective and differential, crystal violet and bile salts
to inhibit gram positive, those that can ferment lactose acidically appear red, negative
appears colorless; determined by neutral red (S. enteriditis, E. coli)
Advantages of Solid Media - ✔️✔️allows for isolation of bacteria as pure culture; mixed
bacteria can be separated
microbial metabolism - ✔️✔️the means by which a microorganism obtains the energy
and nutrients it needs to live and reproduce
agar - ✔️✔️bacteriologically inert
semisolid media - ✔️✔️useful for the cultivation of microaerophilic bacteria or
determination of bacterial motility
all purpose media - ✔️✔️TSA (tryptic soy agar) and TSB (tryptic soy broth)
turbid - ✔️✔️diffusion uniform throughout the broth
sediment - ✔️✔️settles at the bottom
pellicle - ✔️✔️flocculent growth, some may float to the top
endospores - ✔️✔️not readily killed by many antimicrobial treatments (may be central,
terminal, or subterminal)
germination - ✔️✔️not a reproductive process, but a process of differentiation
gram stain - ✔️✔️1. crystal violet
2. iodine mordant
3. ethanol decolorizer
4. safranin counterstain
example of gram positive bacteria - ✔️✔️M. luteus
