This set of Microbiology Multiple Choice Questions & Answers (MCQs) focuses 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?
Explanation: 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
Explanation: 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?
Explanation: 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.
Explanation: Brocothrix are rods often occurring in long, kinked filaments and are facultatively anaerobic.
5. Volutin granules stain which colour with dilute methylene blue?
d) Reddish purple
Explanation: 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
Explanation: 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.
d) rudimentary branching
Explanation: 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?
Explanation: 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?
Explanation: The genus Rothia is aerobic,catalase-positive, and a normal inhabitant of the human mouth.
10. Mycobacteria are acid-fast organisms.
Explanation: 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 __________
Explanation: 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
Explanation: 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.
Sanfoundry Global Education & Learning Series – Microbiology.
To practice all areas of Microbiology, here is complete set of 1000+ Multiple Choice Questions and Answers.