Microbiology Multiple Choice Questions on “World of Bacteria I – Facultatively Anaerobic Gram – Negative Rods”.
1. The cell diameter of bacteria belonging to family Enterobacteriaceae is ____________
A. 1 m
B. 1 cm
C. .3-1.5 micrometre
D. 5 micrometer
Answer: C
Clarification: A distinctive feature of the family Enterobacteriaceae is that the cell diameter is 0.3 to 1.5 micrometers.
2. What is the cell shape of the organisms belonging to the family Enterobacteriaceae?
A. vibrio
B. coccus
C. bacillus
D. straight rod
Answer: D
Clarification: The cell shape of organisms belonging to the family Enterobacteriaceae is that of a straight rod.
3. Enterobacteriaceae possesses endoflagella.
A. True
B. False
Answer: B
Clarification: Enterobacteriaceae possesses lateral flagella and moves by means of it. It does not possess endoflagella.
4. Which of the following genus of bacteria causes gastroenteritis in humans?
A. Salmonella
B. Enterobacter
C. Escherichia
D. Shigella
Answer: C
Clarification: Some bacteria of genus Escherichia causes gastroenteritis and some others can also cause urinary tract infections.
5. Enterobacter sp. gives negative result for Voges-Proskauer test.
A. True
B. False
Answer: B
Clarification: Enterobacter sp. gives positive results for Voges-Proskauer test by giving a reddish-pink colouration.
6. Which of the following genus of bacteria under the family Enterobacteriaceae is mainly associated with plants?
A. Erwinia
B. Serratia
C. Proteus
D. Yersinia
Answer: A
Clarification: Bacteria belonging to the genus Erwinia differ from most other Enterobacteriaceae by being mainly associated with plants. They are often plant pathogens, causing diseases such as blights, leaf spot, wilts, etc.
7. Which of the following is the causative agent of the plague?
A. Y.enterocolitica
B. Y.pestis
C. P.mirabilis
D. E.coli
Answer: B
Clarification: Yersiniae are parasites of animals but can also cause infections in humans. For example, Y.pestis is the causative agent of the plague.
8. The family Vibrionaceae is _________________
A. oxidase-positive
B. oxidase-negative
C. coccus shaped
D. non-motile
Answer: A
Clarification: A distinctive feature of the family Vibrionaceae is that they are usually oxidase-positive. They are motile by means of polar flagella and cell shape is that of curved or straight rods.
9. Which of the following genus shows the characteristic of bioluminescence?
A. Aeromonas
B. Zymomonas
C. Vibrio
D. Haemophilus
Answer: C
Clarification: Some species of genus Vibrio can emit light of a blue-green color(bioluminescence), an oxygen-dependent reaction catalyzed by the enzyme luciferase.
10. Among the given families, which family contains organisms that are non-motile?
A. Enterobacteriaceae
B. Vibrionaceae
C. Pseudomonadaceae
D. Pasteurellaceae
Answer: D
Clarification: Pasteurellaceae contains cells that are nonmotile. Their cell diameter is very small and the shape is that of a straight rod.
11. The X factor and/or the V factor is required by which genus of bacteria?
A. Pasteurella
B. Haemophilus
C. Actinobacillus
D. Zymomonas
Answer: B
Clarification: Haemophilus bacteria is distinguished by unusual nutritional requirements: the X factor (heme, occurring in blooD. and/or the V factor(the coenzyme nicotinamide adenine dinucleotide).
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