Microbiology Multiple Choice Questions on “World of Bacteria II – Nonspore – Forming Gram – Positive Bacteria”.
1. Which of the following Nonspore forming Gram-positive rods show a negative result for catalase test?
A. Lactobacillus
B. Kurthia
C. Brocothrix
D. Renibacterium
Answer: A
Clarification: Lactobacillus which are strictly fermentative organisms show negative result for catalase test.
2. Which of the following is a characteristic of the genus Caryophanon?
A. anaerobic species
B. non-motile organism
C. disk-shaped cells
D. parasitic
Answer: C
Clarification: Caryophanon is unusual as it is composed of large, disk-shaped cells arranged in trichomes. They are aerobic organisms and are motile by peritrichous flagella.
3. Which of the following genus of organisms causes meningitis in adults?
A. Erysipelothrix
B. Listeria
C. Caryophanon
D. Brocothrix
Answer: B
Clarification: The species L.monocytogenes of the genus Listeria is a parasite and causes meningitis in adults and prenatal or postnatal disease in infants.
4. Brocothrix is a facultatively anaerobic genus of species.
A. True
B. False
Answer: A
Clarification: Brocothrix are rods often occurring in long, kinked filaments and are facultatively anaerobic.
5. Volutin granules stain which colour with dilute methylene blue?
A. Violet
B. Blue
C. Red
D. Reddish purple
Answer: D
Clarification: The cells of Corynebacterium accumulate intracellular volutin granules (metachromatic granules) which stain reddish purple with dilute methylene blue.
6. The cell walls of Corynebacterium contain mycolic acid containing ______________ carbon atoms.
A. 2 to 3
B. 100 to 150
C. 32 to 36
D. 20 to 25
Answer: C
Clarification: The cell walls of Corynebacterium contain mycolic acids (corynemycolic acids) containing 32 to 36 carbon atoms.
7. Cells of Arthrobacter in the stationary phase of growth are ____________ shaped.
A. rod
B. irregularly
C. coccoid
D. rudimentary branching
Answer: C
Clarification: Cells of Arthrobacter in the stationary phase of growth are distinctly coccoid; when these are inoculated into fresh media, they give rise to rod-shaped cells.
8. Which of the following genus of species occur on the surface of certain cheeses such as brick and Limburger?
A. Brevibacterium
B. Microbacterium
C. Cellulomonas
D. Arthrobacter
Answer: A
Clarification: B.linens of the Brevibacterium has its usual habitat on the surface of certain cheeses such as brick and Limburger, where it produces proteolytic enzymes that aid in the cheese-ripening process.
9. Which of the following genus of organisms are normal inhabitants of the human mouth?
A. Agromyces
B. Arachnia
C. Actinomyces
D. Rothia
Answer: D
Clarification: The genus Rothia is aerobic,catalase-positive, and a normal inhabitant of the human mouth.
10. Mycobacteria are acid-fast organisms.
A. True
B. False
Answer: A
Clarification: A major characteristic of mycobacteria is that they are acid-fast; that is, once stained with aniline dyes, they are difficult to decolourize, even when treated with a mixture of acid and alcohol.
11. The causative agent of leprosy is __________
A. M.intracellulare
B. M.leprae
C. M.kansasii
D. M.phlei
Answer: B
Clarification: Mycobacterium leprae is the causative agent of leprosy. They may be slightly curved or straight rods.
12. The walls of Nocardioforms contains the sugars ____________
A. sucrose and galactose
B. fructose and galactose
C. sucrose and arabinose
D. arabinose and galactose
Answer: D
Clarification: The walls of Nocardioforms contain the sugars arabinose and galactose. The peptidoglycan contains meso-diaminopimelic acid and no glycine interpeptide bridges occur between the peptidoglycan chains.
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