History Of General Microbiology And Immunology Multiple choice Question And Answers

General Microbiology And Immunology Multiple choice Question And Answers

1. Which of the following organism(s) is/are not cultivable?

1. Mycobacterium leprae
2. Klebsiella rhinoscleromatis
3. Rhinosporidium seeberi
4. Pneumocystis jiroveci

Answer. (1, 3, 4) (Mycobacterium leprae, Rhinosporidium seeberi, Pneumocystis jiroveci)

• M. leprae and T. pallidum are not cultivable.
• Among fungi, Rhinosporidium, Pneumocystis, and Lacazia are not cultivable.

Read And Learn More: Micro Biology And Immunology Multiple Choice Question And Answers

2. Syphilis was discovered in which year?

1. 1838
2. 1905
3. 1906
4. 1921

Answer. (2) (1905)

• Treponema pallidum, the agent of syphilis was discovered on 1905 by Schaudinn and Hoffmann..

3.  All are Koch’s postulates except:

1. A microorganism should be constantly associated with the lesions of the disease
2. It should be possible to isolate the bacterium in pure culture from the lesions
3. Inoculation of such pure culture into laboratory animals should reproduce the lesions
4. Administration of broad-spectrum antimicrobial agent dependably eradicates the organisms and cures the diseases

Answer. (4) (Administration of broad-spectrum antimicrobial agent dependably eradicates the organisms and cures the diseases)

4. Corynebacterium diphtheriae is also called:

1. Koch’s bacillus
2. Kleb-Loeffler bacillus
3. Roux bacillus
4. Yersin bacillus

Answer. (2) (Kleb-Loeffler’s…)

Corynebacterium diphtheriae is also called Klebs-Loeffler bacillus

5. Leeuwenhoek is associated with:

1. Telescope
2. Microscope
3. Stains
4. Immunization

Answer. (2) (Microscope)

• Antony van Leeuwenhoek from Holland was the first person to observe and describe microorganisms accurately by using lenses and was considered as the founder of simple microscope (1694).
• Zacharias Jansen and his father described the first compound microscope
• Ernst Ruska: Invented Electron Microscope in 1931.

6. Louis Pasteur is associated with all except:

1. Vaccination of smallpox
2. Germ theory
3. Pasteurization
4. Vaccination of rabies

Answer. (1) (Vaccination of..)

• Vaccination of smallpox by using cowpox was proposed by Edward Jenner.
• Louis Pasteur prepared the vaccines for Anthrax, Rabies, Cholera (CAR)
• For other contributions of Louis Pasteur- Refer chapter review.

7. Gram-negative cell wall contains?

1. Peptidoglycan
2. Lipopolysaccharides
3. Lipids
4. Teichoic acid
5. All of the above

Answer. (1, 2, 3) (Peptidoglycan, Lipopolysaccharides, Lipids)

• Teichoic acid is a part of Gram-positive cell wall.

8. Which is not a prokaryote?

1. Mycoplasma
2. Rickettsiae
3. Shigella
4. Entamoeba

Answer. (4) (Entamoeba)

• Parasites and fungi are eukaryotes (Entamoeba is a parasite); whereas bacteria and blue green algae are prokaryotes.

9. Non motile:

1. Shigella
2. E.coli
3. Proteus
4. Vibrio

Answer. (1) (Shigella)

• Shigella, Klebsiella are Non Motile among Gram negative Enterobacteriaceae organisms.

10. Swarming is seen in:

1. Clostridium tetani
2. Clostridium perfringens
3. Clostridium botulinum
4. Clostridium difficile

Answer. (1) (Clostridium tetani)

• Swarming is exhibited by- Cl. tetani, Proteus, Vibrio parahemolyticus and Vibrio alginolyticus.

11. Which is a eukaryote?

1. Mycoplasma
2. Bacteria
3. Fungus
4. Chlamydia

Answer. (3) (Fungus)

• Prokaryotes include bacteria and blue-green algae
• Eukaryotes include fungi, algae (other than blue-green), protozoa, helminths, and slime moulds.

12. Role of bacterial capsule is:

1. Support
2. Transport
3. Antiphagocytic
4. Adhesion

Answer. (3 > 4) (Antiphagocytic > Adhesion)

• The main role of bacterial capsule is to escape from phagocytosis. Capsule also helps in biofilm formation and adhesion.

13. Capsulated organism:

1. Candida
2. Klebsiella
3. Proteus
4. Cryptococcus
5. Histoplasma

Answer. (2) and (4) (Klebsiella and Cryptococcus)

• List of capsulated micro-organisms-Refer text

14. Which is not present in Gram-negative bacteria?

1. Peptidoglycan
2. Teichoic acid
3. LPS
4. Porin channels

Answer. (2) (Teichoic acid)

15. Craigie’s tube method is used to differentiate:

1. Motile and nonmotile strains
2. Virulent and avirulent strains
3. Capsulated and non capsulated strains
4. Rough and smooth strains

Answer. (1) (Motile and nonmotile strains)

16. Which of the following is TRUE regarding electron microscopy?

1. There is a risk of radiation leakage
2. Can magnify up to 30,000 times
3. Both fixed and living specimens can be studied
4. Vacuum is not required for proper functioning
5. Black and white image

Answer. (1, 5) (There is a risk of radiation leakage, Black and white image)

• There is a risk of radiation hazard in electron microscope as X-ray are produced X-rays are produced whenever the primary electron beam strike metal parts
• Can magnify up to 1,00,000 times
• Only fixed specimens can be studied, not living specimens
• Vacuum is required for proper functioning
• It produces black and white image

17. A patient is having thick, gray coating on the throat and tonsils, followed with fever, chills and swollen glands for a week. Microscopic examination of nasopharyngeal or pharyngeal swab showed Gram-positive organism with a special stain. The constitutes of the stain are:

1. Crystal violet, Gram’s iodine
2. Toluidine blue, malachite green, glacial acetic
3. Carbol fuchsin, acid alcohol, and methylene blue
4. Methylene Blue

Answer. (2) (Toluidine blue, malachite green, glacial acetic)

• Thick, gray coating on the throat and tonsils, followed with fever, chills… suggestive of diphtheria
• Special stain used for diphtheria is- Albert stain, to demonstrate metachromatic granules
• Composition of Albert stain include-
• Albert A: Toludine blue, Malachite green, Glacial acetic acid, Alcohol (95% ethanol), Distilled water
• Albert B: Idoine in potassium iodide

18. Which of the following labels corresponds to the condenser of the microscope?

1. A
2. B
3. C
4. D

Answer. (3) (C)

• A- denotes head,
• B- denotes objective,
• C- denotes condenser,
• D- denotes base

19. Factor affecting electron microscope is:

1. Eyepiece
2. Wavelength of the light
3. Type of glass lens used
4. Thickness of the sample

Answer. (4) (Thickness of the sample)

• In order to get visualized by EM, the specimen should be very thin (20 to 100 nm thickness).

20. Resolving power of microscope depends on all except:

1. Refractive index of medium
2. Wavelength
3. Diameter of aperture
4. Focal length of objective lens

Answer. (4) (Focal length of objective lens)

• Resolving power of microscope depends on wavelength and numerical aperture (the latter is in turn depends on refractive index angular aperture).

21. What is the reason for decolorization in Gram-negative bacilli in Gram staining?

1. Due to the two dyes used in staining
2. Lipid content
3. Cell membrane integrity
4. Teichoic acid.

Answer. (2) (Lipid content)

• Gram-negative bacteria gets decolorized easily due to following factors-
• 1) Thin peptidoglycan layer and less cross linking,
• 2) Presence of lipid rich lipopolysaccharide layer which gets easily destroyed by decolorizer.

22. Which of the following structures is required in the microscope for taking this type of image?

1. Darkfield condenser
2. Phase plate
3. Dichroic mirror
4. Cathode ray tube

Answer. (3) (Dichroic mirror)

• The given image is a Fluorescence microscopy photograph. The components of a fluorescence microscope are a light source (e.g. mercury lamp), the excitation filter, the dichroic mirror and the emission filter.
• The exciting rays then get reflected by a dichromatic mirror in such a way that they fall on the specimen which is priorly stained by fluorescent dye. Then the specimen is focused under the microscope.

Other options:

Answer.Darkfield condenser—required for Darkfield microscope

Phase plate—required for Phase contrast microscope

Cathode ray tube—required for Electron microscope.

23. Composition of ZN stain are all except:

1. Basic fuchsin
2. Acid fuchsin
3. Phenol
4. Alcohol

Answer. (2) (Acid fuchsin)

• ZN stain has three components:
• Primary stain: Basic fuchsin + Phenol
• Decolorizer: Sulfuric acid or acid-alcohol
• Counterstain: Methylene blue or Malachite Green

24. Acid-fast bacilli stained by:

1. Ziehl–Neelsen
2. Albert
3. Neisser
4. Ponder

Answer. (1) (Ziehl–Neelsen)

25. Correct sequence in Gram staining?

1. Methyl violet → Iodine → Acetone → Carbol fuchsin
2. Carbol fuchsin → Iodine → Acetone → Methyl violet
3. Methyl violet → Acetone → Iodine → Carbol fuchsin
4. Methyl violet → Carbol fuchsin → Acetone → Iodine

Answer. (1) (Methyl violet → Iodine → Acetone → Carbol fuchsin)

26. Not used in Gram’s staining:

1. Methylene blue
2. Crystal violet
3. Iodine
4. Safranin

Answer. (1) (Methylene blue)

27. Indian ink staining is positive for which of the following cocci?

1. Pneumococcus
2. Staphylococcus
3. Meningococcus
4. Gonococcus
5. Enterococcus

Answer. (1, 3) (Pneumococcus, Meningococcus)

India ink stain is used to demonstrate the capsule. Among cocci, Pneumococcus, Meningococcus are capsulated.

28. Sporulation occurs in:

1. Lag phase
2. Log phase
3. Stationary phase
4. Decline phase

Answer. (3) (Stationary phase)

29. Which of these bacteria grow in acidic pH?

1. Lactobacillus
2. Klebsiella
3. Salmonella
4. Vibrio

Answer. (1) (Lactobacillus)

• Lactobacillus can grow in acidic pH; Vibrio can grow in alkaline pH.

30. Which event takes place lag phase of growth curve?

1. Bacterial cell number increase
2. Bacterial cell size increase
3. Sporulation

Answer. (2) (Bacterial cell size increase)

31. Which of the following is microaerophilic?

1. Campylobacter
2. Vibrio
3. Bacteroides
4. Pseudomonas

Answer. (1) (Campylobacter)

• Microaerophilic: Require small amount of oxygen (5%) e.g. Campylobacter, Helicobacter and Mycobacterium bovis.

32. The term viable not cultivable is used for:

1. M. leprae
2. M. tuberculosis
3. Treponema pallidum
4. Salmonella
5. Staphylococcus

Answer. (1, 3) (M. lepare and Treponema pallidum)

33. Correct sequence of bacterial growth curve:

1. Log phase Lag Phase Stationary phase Decline phase
2. Lag Phase Log phase Stationary phase Decline phase
3. Stationary phase Log phase Lag Phase Decline phase
4. Lag phase Exponential phase Log phase Death phase
5. Exponential phase Lag phase Death phase Stationary

Answer. (2) (Lag- Log- Stationary- Decline)

34. Population doubling time in coliform bacilli is:

1. 20 seconds
2. 20 minutes
3. 20 hours
4. 20 days

Answer. (2) (20 minutes)

• Population doubling time or the generation time of- E. coli- 20 min, M. tuberculosis-20 hr and M. leprae-20 days

35. Phototropism means:

1. Growing towards the sunlight
2. Obtaining energy from sunlight
3. Reflecting energy from light source
4. None of the above

Answer. (2) (Obtaining energy from sunlight)

• Phototrophs obtain energy from sunlight, chemotrophs from chemical reaction, and autotrophs can synthesize all their organic compounds.

36. A health center reports 40 to 50 cases in a week in the community. This week they reported 48 cases. This is called:

1. Epidemic
2. Sporadic
3. Endemic
4. Outbreak

Answer. (3) (Endemic)

• Endemic: The infections that occur at a persistent, usually low level in a certain geographical area are called endemic
• Epidemic: The infections that occur at a much higher rate than usual in a particular geographic area is known as epidemic
• Pandemic: Infection that spreads rapidly over large areas of the world is known as pandemic
• Sporadic: Infections occur at irregular intervals or only in a few places; scattered or isolated.

37. Which is not an example of direct transmission?

1. Transplacental
2. Soil
3. Respiratory
4. Sexual

Answer. (2) (Soil)

38. Which of the following bacteria is transmitted by Housefly?

1. Leptospira
2. Listeria
3. V. cholerae
4. Yersinia

Answer. (3) (V. cholerae)

Houseflies (Musca domestica) has a potential role in the transmission of Vibrio cholerae in India.

39. Motile and non-motile bacteria differentiated by all except:

1. Gram stain
2. Craigie tube
3. Flagellar stain
4. Hanging drop

Answer. (1) (Gram stain)

40. All of these properties can be attributed to biofilms except:

1. Helps in adhesion
2. Increase antibiotic entry into the cell
3. Decreased metabolism
4. Acts as a mechanical barrier

Answer. (2) (Increase antibiotic entry into the cell)

Biofilm formation results in decrease antibiotic entry into the bacterial cell.

41. Obligate intracellular organism is:

1. Mycoplasma
2. Chlamydia
3. Cryptococcus
4. Helicobacter

Answer. (2) (Chlamydia)

42. True about exotoxin:

1. LPS in nature
2. Heat stable
3. Not antigenic
4. Toxoid can be prepared

Answer. (4) (Toxoid can be prepared)

43. All the following are true regarding exotoxin except:

1. Highly antigenic
2. Heat stable
3. Neutralized by antibody
4. Active in very minute doses

Answer. (2) (Heat stable)

Exotoxins are heat labile and destroyed at 60°C.

44. All the following statements are true regarding endotoxins except:

1. Neutralized by specific antibodies
2. Heat stable
3. Somatic antigen
4. Poorly antigenic

Answer. (1) (Neutralized by specific antibodies)
Exotoxins are neutralized by specific antibodies, but not endotoxins.