Culture Media Multiple Choice Questions
1. Which one of the following is true
A. Nutrient broth is basal medium
B. Addition of selective substances in a solid medium is called enrichment media
C. Agar has nutrient properties
D. Chocolate medium is selective medium
Answer: Nutrient broth is basal medium
2. Which of the following bacteria has the lowest 50% infective dose (ID50)?
A. Shigella sonnei
B. Campylobacter jejuni
C. Salmonella typhi
D. Vibrio cholerae
Answer: Shigella sonnei
3. The cogulase test is used to differentiate
A. Staphylococcus aureus from Staphylococcus epidermidis
B. Streptococcus pyogens from Enterococcus faecalis
C. Staphylococcus epidermidis from Neisseria meningitidis
D. Streptococcus pyogens from Staphylococcus aureus
Answer: Staphylococcus aureus from Staphylococcus epidermidis
4. The identification of bacteria by serologic tests is based on the presence of specific antigens. Which of the following bacterial components is least likely to contain useful antigens?
A. Ribosomes
B. Cell wall
C. Capsule
D. Flagella
Answer: Ribosomes
5. Each of the following statements concerning the Gram stain is correct except:
A. Mycobacterium tuberculosis stains blue because it has a thick lipid layer
B. Escherichia coli stains pink because it has a thin peptidoglycan layer
C. Streptococcus pyogens stains blue because it has a thick peptidoglycan layer
D. Mycoplasma pneumoniae is not visible in the Gram’s stain because it does not have a cell wall
Answer: Mycobacterium tuberculosis stains blue because it has a thick lipid layer
6. Each of the following organisms is an important cause of urinary tract infections except:
A. Bacteriodes fragilis
B. Klebsiella pneumoniae
C. Proteus mirabilis
D. None Of These
Answer: Bacteriodes fragilis
7. A 30 year old woman has non-bloody diarrhea for the past 14 hours. Which one of the to following organisms is least likely to cause this illness?
A. Salmonella enteritidis
B. Clostridium difficile
C. Streptococcus pyogens
D. none of the above
Answer: Streptococcus pyogens
8. Each of the following agents is a recognized cause of diarrhea except
A Enterococcus faecalis
B Escherichia coli
C Clostridium perfringens
D Vibrio cholerae
Answer: Enterococcus faecalis
9. Which of the following disease is best diagnosed by serologic means?
A. Q Fever
B. Actinomycosis
C. Pulmonary tuberculosis
D. Gonorrhea
Answer: Q Fever
10. In pour-plate method,the medium should be maintained at what temperature?
A. 67 degree C
B. 37 degree C
C. 0 degree C
D. 45 degree C
Answer: 45 degree C
11. Which of the following method can be used to determine the number of bacteria quantitatively?
A Pour-plate and spread plate
B Streak-plate
C Spread-plate
D Pour plate
Answer: Pour-plate and spread plate
12. Which of the following are not performed in lyophilization?
A bacterial sample is dehydrated
B cell suspension is frozen at -60 degree to -78 degree C
C vials are connected to high-vacuum line
D agar slant is covered with mineral oil
Answer: agar slant is covered with mineral oil
13. What is the temperature of liquid nitrogen?
A -196 degree C
B -150 degree C
C 0 degree C
D None Of The Above
Answer: -196 degree C
14. Which of the following is a characteristic of beef extract?
A aqueous extract of lean beef tissue
B aqueous extract of yeast cells
C complex carbohydrate obtained from certain marine algae
D product resulting from the digestion of proteinaceous materials
Answer: aqueous extract of lean beef tissue
15. Which of the following is a rich source of B vitamins?
A Yeast extract
B Beef extract
C Peptone
D Agar
Answer: Yeast extract
16. Nutrient broth, a liquid media contains beef extract and peptone respectively in how much amounts?
A 0.3%, 0.5%
B 0.7%, 0.3%
C 0.2%, 0.4%
D 0.1%, 0.6%
Answer: 0.3%, 0.5%
17. Which of the following is a Complex media for fungal growth?
A Potato Dextrose Agar(PDA) media
B Mac Conkey Agar media
C Nutrient broth
D Luria-Bertani media
Answer: Potato Dextrose Agar(PDA) media
18. Which of the following are functions of Maintenance Media?
A used for the maintenance of the viability and physiological characteristics
B used for determining the type of growth produced by bacteria
C used for assay of vitamins,amino acids
D used for determining the bacterial content
Answer: used for the maintenance of the viability and physiological characteristics
19. Which of the following bacteria requires nicotinic acid as a growth factor in their media?
A Nitrosomonas sp
B E. coli
C Proteus vulgaris
D none of the above
Answer: Proteus vulgaris
20. Which of the following instrument is used for sterilizing the media after it has been prepared?
A Incubator
B Inoculum Needle
C Laminar Air Flow Chamber
D Autoclave
Answer: Autoclave
21. The isolation of gonorrhea-causing organism, Neisseria gonorrhoeae by the use of certain antibiotics in media is an example of which of the following?
A Selective media
B Assay media
C Differential media
D Enriched media
Answer: Selective media
22. Which of the following is used as a solidifying agent for media?
A Agar
B Yeast extract
C Beef extract
D Peptone
Answer: Agar
23. Which device is used to pick a single bacterial cell from a mixed culture?
A Micromanipulator
B Micropipette
C Microscope
D Microprobe
Answer: Micromanipulator
24. Nichrome loop wire is used in which of the following techniques?
A Streak-plate
B Pour-plate
C Spread-plate
D Roll-tube technique
Answer: Streak-plate
25. Which of the following is a function of cryoprotective agents?
A to trap the liquid nitrogen
B for long-term preservation of cultures
C prevents formation of ice
D prevents cell damage due to ice crystal formation
Answer: prevents cell damage due to ice crystal formation
26. Roll-tube technique is used to isolate ___________
A Stringent Anaerobes
B Facultatives
C Aerobes
D None Of These
Answer: Stringent Anaerobes
27. An outbreak of sepsis caused by Staphylococcus aureus has occurred in the newborn nursery. You are called upon to investigate. According to your knowledge of the normal flora, what is the most likely source of the organism?
A Throat
B Colon
C Nose
D none of the above
Answer: Nose