Exam (elaborations)
Microbiology Tests Questions and Answers 2024
- Course
- Institution
Exam of 5 pages for the course microbiology at microbiology (Microbiology Tests)
[Show more]
Content preview
Microbiology TestsWhat are the reagents used for gram staining? (4) - answer Crystal violet (stains all
cells purple)
Gram's iodine (binds with dye forming large crystals)
95% ethanol or acetone (removes unbound dye, gram negative will now be colorless)
Safranin (now gran negative appears pink)
Name 3 types of all purpose media – answer BAP (sheep blood agar)
NA (nutrient agar)
TSA (tryptic soy agar)
Provide the definition for "all-purpose media" - answer support the growth of a wide
variety of bacteria; contain all required nutrients need; do not contain inhibitors to
bacterial growth
Provide a definition for "enrichment media" - answer Contain substances that enhance
the growth of bacteria. Example: chocolate agar
Provide a definition for "selective media" - answer Media that has antimicrobial
substances added, thus inhibiting some bacteria while allowing others to grow.
Examples: Columbia CNA agar, Mac agar, mannitol salt agar
Provide a definition for "differential media" - answer Media used to distinguish between
bacterial types by identifying specific enzymes the bacteria possess. The media
characteristics or color will chance because of the enzyme. Examples: MAC, mannitol
salt agar, MRSA agar
List 3 types of selective media - answerColumbia CNA agar
MacConkey agar (MAC)
Mannitol salt agar
Name Columbia CNA agar's inhibitors (antimicrobial substances) & then what
organisms grow and which are inhibited - answerinhibitors: colistin, nalidixic acid
grows: gram positive
inhibited: gram negative
Name MAC agar's inhibitors (antimicrobial substances) & then what organisms grow
and which are inhibited - answerinhibitors: bile sats, crystal violet
grows: gram negative
inhibited: gram positive
, Name Mannitol Salt agar's inhibitors (antimicrobial substances) & then what organisms
grow and which are inhibited - answerinhibitors: sodium chloride
grows: staphlycoccus species
inhibited: most other bacteria
Name the 3 types of differential media & what they differentiate - answerMAC agar: pink
colonies are lactose fermenters, clear colonies are lactose nonfermenters
Mannitol Salt agar: staph aureus colonies are yellow, other colonies are not yellow
MRSA agar: methicillin0resistant staph colonies will grow, meticillin-sensitive colonies
will not grow
What grows on a BAP? - answeranything
What grows on Choc? - answeranything + haemophilus (needs growth factors)
What grows on MAC? - answergram negative rods
pink=lactose fermentation
What grows on CNA? - answergram positive cocci
Which media distinguishes between types of hemolysis reactions? - answerBAP
Discuss the 3 types of hemolysis - answerAlpha-partial destruction of RBC, green zone
Beta-total destruction of RBC, clear zone
Gamma-lack hemolysin that attacks RBC, no zone of hemolysis
Name the reagent for the catalase test - answer3% hydrogen peroxide added to slide
+ bubbles means there is oxygen and thus enzyme catalase broke down hydrogen
peroxide
- no bubbles means there is no oxygen and hydrogen peroxide was not broken down
(no enzyme catalase)
(differentiates between staph and strep)
Name the reagent for the coagulase test - answerrabbit plasma added to slide
immediate clumping= + for coagulase (protein for clotting, means it is staph aureus)
no clumping (15 sec) = - for coagulase (thus it is coagulase negative staph)
What is the optochin test for and what does it involve? - answerdifferentiates between
strep pneumoniae and other alpha strep
BAP--spread bacteria--put optochin disc on--incubate--next day look for growth/no
growth
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller julianah420. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $14.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
84146 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now