Media
Biochemical Tests
What am I?
Prokaryotes
Gram Stains
100
Is sheep blood agar (SBA) nutrient or enriched?
Nutrient
100
What test differentiates Staphylococcus from Streptococcus?
Catalase: Staph (+) and Strep (=)
100
I am a GPC CH, am catalase negative, and can be a normal flora of the throat and skin, but I can also give you a sore throat. What am I?
Streptococcus pyogenes
100
Name 3 internal structures of a prokaryotic cell.
Nucleoid, Plasmids (in some organisms), Ribosomes, Inclusions (many types possible), and Endospores (in some organisms)
100
What are the primary and secondary stains used?
The primary stain is crystal violet and the secondary stain is safranin
200
What type of organisms grow on chocolate (CHOC) agar?
Fastidious organisms
200
This test detects s bacteria's ability to decompose the amino acid __________ into indole.
Tryptophan
200
I am a GNB, grow pink on MAC, am a normal flora of the colon (large intestine), but I can also cause neonatal meningitis. What am I?
Escherichia coli
200
Name two functions of the glycocalyx
Protects organism from phagocytosis → Increases virulence, Adherence to specific surfaces → e.g. rocks, respiratory tract, Source of nutrients, Prevents dehydration
200
Describe this stain.
Gram positive bacilli in chains......this is actually an image of Bacillus anthracis (ANTHRAX!!!!!)
300
What side of this maconkey (MAC) plate is growing a LACTOSE FERMENTOR?
The pink (left) side
300
What enzyme does an oxidase tests detect?
Cytochrome oxidase
300
I am a GPC CL, am catalase positive, am a normal flora of the skin, throat, and intestines, but I can also cause endocarditis and Toxic Shock Syndrome. What am I?
Staphylococcus aureus
300
What organisms are endospores primarily found in?
Gram positive organisms
300
Describe this stain.
Gram negative cocci in clusters
400
What is the difference between nutrient and enriched growth media?
Nutrient media is general for most bacteria, while enriched has specific added growth factors (blood, vitamins, yeast, etc.) to enhance the growth of some fastidious organisms
400
What method tests a bacteria's ability to ferment glucose, lactose, and sucrose, and if the bacteria can produce gas or make H2S?
Triple Sugar Iron (TSI)
400
I am a GNB, oxidase positive, am a normal flora of the skin, throat, an intestines, but can also grow inside wounds and burn infections. I also smell like grapes! What am I?
Pseudomonas aeruginosa
400
What structure in the cell wall determines whether an organism will stain as a gram positive or gram negative bacteria?
Peptidoglycan (murein)
400
What is the purpose of the mordant (Gram's iodine) in a gram stain?
It combines with crystal violet in the cell wall to form a crystal violet–iodine complex, allowing in to be trapped in gram positive cell walls due to the multiple peptidoglycan layers