Dear Medical Laboratory Professionals,
Welcome to our collection of 2000 Multiple Choice Questions (MCQs) on Microbiology, specially designed for medical laboratory practitioners. This resource is here to help you improve your knowledge and skills in microbiology, a key part of medical laboratory science.
We hope this resource not only aids in your professional growth but also deepens your appreciation for the fascinating world of microbiology. Happy studying!
1. Jumping gene is known as:
A. Transposon ✅
B. Episome
C. Cosmid
D. Plasmid
A. Transposon ✅
B. Episome
C. Cosmid
D. Plasmid
2. Staphylococcus bacteria secrete all, EXCEPT:
A. Lipase
B. Cellulase ✅
C. Coagulase
D. Lecithinase
A. Lipase
B. Cellulase ✅
C. Coagulase
D. Lecithinase
3. The following test is used to differentiate Streptococcus from Staphylococcus:
A. Coagulase test
B. Catalase test ✅
C. Phosphatase
D. Indole test
A. Coagulase test
B. Catalase test ✅
C. Phosphatase
D. Indole test
4. Quellung reaction is due to ________ swelling.
A. Capsular ✅
B. Flagellar
C. RBC
D. Ribosomal
A. Capsular ✅
B. Flagellar
C. RBC
D. Ribosomal
5. Gram negative cocci is:
A. Staphylococcus
B. Streptococcus
C. Neisseria ✅
D. Salmonella
A. Staphylococcus
B. Streptococcus
C. Neisseria ✅
D. Salmonella
6. Medusa head colony is found in:
A. Clostridium
B. Bacillus
C. Pseudomonas ✅
D. E. coli
A. Clostridium
B. Bacillus
C. Pseudomonas ✅
D. E. coli
7. All of the following are acid fast bacteria except:
A. Cryptosporidium
B. Mycoplasma ✅
C. Mycobacterium
D. Nocardia
A. Cryptosporidium
B. Mycoplasma ✅
C. Mycobacterium
D. Nocardia
8. Widal test is an example of:
A. Flocculation
B. Precipitation
C. Agglutination ✅
D. Both “A” and “B”
A. Flocculation
B. Precipitation
C. Agglutination ✅
D. Both “A” and “B”
9. Genome of Herpes Simplex Virus comprised of:
A. ssDNA
B. dsDNA ✅
C. ssRNA
D. dsRNA
A. ssDNA
B. dsDNA ✅
C. ssRNA
D. dsRNA
10. The following methods are used for serological diagnosis, EXCEPT:
A. CFT
B. PCR ✅
C. SRH
D. Western blot
A. CFT
B. PCR ✅
C. SRH
D. Western blot
11. Which of the following virus is not associated with respiratory infections?
A. Rotavirus ✅
B. Adenovirus
C. Influenza virus
D. RSV
A. Rotavirus ✅
B. Adenovirus
C. Influenza virus
D. RSV
12. HCV belongs to genus:
A. Togavirus
B. Flavivirus
C. Filovirus
D. Retrovirus ✅
A. Togavirus
B. Flavivirus
C. Filovirus
D. Retrovirus ✅
13. HIV infects most commonly:
A. CD4+ cells ✅
B. CD8+ cells
C. B-lymphocytes
D. Basophils
A. CD4+ cells ✅
B. CD8+ cells
C. B-lymphocytes
D. Basophils
14. Aflatoxin is produced by:
A. Candida
B. Penicillium
C. Aspergillus flavus ✅
D. Clostridium
A. Candida
B. Penicillium
C. Aspergillus flavus ✅
D. Clostridium
15. Which one is an essential part of life cycle of Toxoplasma gondii is spread by:
A. Dog
B. Cat ✅
C. Human
D. Sheep
A. Dog
B. Cat ✅
C. Human
D. Sheep
16. Helper cells belong to:
A. T cells ✅
B. B cells
C. Macrophages
D. Monocytes
A. T cells ✅
B. B cells
C. Macrophages
D. Monocytes
17. All of these are antigen presenting cells EXCEPT:
A. T cells ✅
B. B cells
C. Dendritic cells
D. Langerhans cells
A. T cells ✅
B. B cells
C. Dendritic cells
D. Langerhans cells
18. Vaccination is based on the principle of:
A. Agglutination
B. Phagocytosis
C. Immunological memory ✅
D. Clonal deletion
A. Agglutination
B. Phagocytosis
C. Immunological memory ✅
D. Clonal deletion
19. Reaction of soluble antigen with antibody is _______.
A. Agglutination
B. Precipitation ✅
C. Flocculation
D. CFT
A. Agglutination
B. Precipitation ✅
C. Flocculation
D. CFT
20. Which of the following is not included in intrinsic determinants of a disease?
A. Specie
B. Environment
C. Genetics
D. Both “A” and “B” ✅
A. Specie
B. Environment
C. Genetics
D. Both “A” and “B” ✅
21. Preliminary screening can be done by:
A. restriction enzyme
B. dyes
C. antibiotics ✅
D. radiation
A. restriction enzyme
B. dyes
C. antibiotics ✅
D. radiation
22. Which of the following substance can only induce immune response after binding to a larger molecule?
A. Antigen
B. Virus
C. Hapten ✅
D. Antibody
A. Antigen
B. Virus
C. Hapten ✅
D. Antibody
23. To identify participants based on their disease / outcome status, compare presence of risk factor:
A. Case-control ✅
B. Experimental
C. Cross-sectional
D. None of these
A. Case-control ✅
B. Experimental
C. Cross-sectional
D. None of these
24. ___ is an example of arthropod vector borne disease?
A. Avian influenza
B. Tuberculosis
C. Spirochetosis
D. CRD ✅
A. Avian influenza
B. Tuberculosis
C. Spirochetosis
D. CRD ✅
25. Latent infection is seen in viral infections EXCEPT:
A. HIV
B. EBV
C. Rotavirus ✅
D. Cytomegalovirus (CMV)
A. HIV
B. EBV
C. Rotavirus ✅
D. Cytomegalovirus (CMV)
26. Endotoxin for Gram-negative organism is:
A. Polysaccharide
B. Glycoprotein
C. Lipoprotein
D. Lipopolysaccharide ✅
A. Polysaccharide
B. Glycoprotein
C. Lipoprotein
D. Lipopolysaccharide ✅
27. Which of the following is not an oncogenic virus?
A. HTLV-1
B. Adenovirus ✅
C. Papilloma virus
D. HBV
A. HTLV-1
B. Adenovirus ✅
C. Papilloma virus
D. HBV
28. Which of the following is obligate anaerobe?
A. Clostridium ✅
B. Bacillus
C. Staphylococcus
D. Klebsiella
A. Clostridium ✅
B. Bacillus
C. Staphylococcus
D. Klebsiella
29. ______ refers only to the number of new cases of a disease occurring in a given period.
A. % positivity
B. Prevalence
C. Hyperendemic
D. Incidence ✅
A. % positivity
B. Prevalence
C. Hyperendemic
D. Incidence ✅
30. Fungi that possess a capsule is:
A. Candida
B. Aspergillus
C. Cryptococcus ✅
D. Mucor
A. Candida
B. Aspergillus
C. Cryptococcus ✅
D. Mucor
31. The lethal dose required to kill 50% of the lab animals tested under standard called____.
A. ID50
B. MLD50
C. TCIC50
D. LD50 ✅
A. ID50
B. MLD50
C. TCIC50
D. LD50 ✅
32. All are used in Gram’s staining, EXCEPT:
A. Methylene blue
B. Iodine
C. Safranin
D. Crystal violet ✅
A. Methylene blue
B. Iodine
C. Safranin
D. Crystal violet ✅
33. Viruses do not contain:
A. DNA
B. RNA
C. Enzyme
D. Cell wall ✅
A. DNA
B. RNA
C. Enzyme
D. Cell wall ✅
34. ________ is chain forming, & round shaped bacteria.
A. Pneumococcus
B. Streptococcus ✅
C. Staphylococcus
D. Diplococcus
A. Pneumococcus
B. Streptococcus ✅
C. Staphylococcus
D. Diplococcus
35. All the following can be zoonotic EXCEPT:
A. Influenza A H5N1
B. Hantaviruses
C. Poliomyelitis ✅
D. Rabies
A. Influenza A H5N1
B. Hantaviruses
C. Poliomyelitis ✅
D. Rabies
36. Presence of maternal Abs ____ the effect of vaccine.
A. Antagonize
B. Enhance
C. Synergize
D. Complement ✅
A. Antagonize
B. Enhance
C. Synergize
D. Complement ✅
37. A diagnostic test lacking in ________ results in false positive results.
A. Specificity ✅
B. Predictive value
C. Sensitivity
D. Reproducibility
A. Specificity ✅
B. Predictive value
C. Sensitivity
D. Reproducibility
38. Which one of the following is NOT included in innate immune response?
A. phagocytosis
B. complement activation
C. antibodies production ✅
D. NK cells activation
A. phagocytosis
B. complement activation
C. antibodies production ✅
D. NK cells activation
39. Viruses are:
A. Obligate intracellular parasites ✅
B. Have their own metabolism
C. Divide by binary fission
D. Have both DNA and RNA
A. Obligate intracellular parasites ✅
B. Have their own metabolism
C. Divide by binary fission
D. Have both DNA and RNA
40. The vector of plague is:
A. Flies
B. Mosquitoes
C. Ticks
D. Fleas ✅
A. Flies
B. Mosquitoes
C. Ticks
D. Fleas ✅
41. Positive tuberculin test is an example of:
A. hypersensitivity type-I
B. hypersensitivity type-II
C. hypersensitivity type-III
D. hypersensitivity type-IV ✅
A. hypersensitivity type-I
B. hypersensitivity type-II
C. hypersensitivity type-III
D. hypersensitivity type-IV ✅
42. Process of binding primer to DNA template is called:
A. Denaturation
B. Annealing ✅
C. Extension
D. Bounding
A. Denaturation
B. Annealing ✅
C. Extension
D. Bounding
43. _________ reagent is used to precipitate DNA?
A. Isopropanol ✅
B. SDS
C. Phenol
D. Chloroform
A. Isopropanol ✅
B. SDS
C. Phenol
D. Chloroform
44. _________ enzyme is used to synthesize DNA using an mRNA template.
A. Taq polymerase
B. Alkaline Phosphatase
C. Reverse transcriptase ✅
D. Nuclease
A. Taq polymerase
B. Alkaline Phosphatase
C. Reverse transcriptase ✅
D. Nuclease
45. Making routine observations on health, productivity & environment is called as:
A. GIS
B. Monitoring
C. Surveillance ✅
D. Cohort studies
A. GIS
B. Monitoring
C. Surveillance ✅
D. Cohort studies
46. _____ disease is transmitted from parrot to human?
A. Typhoid
B. Bird flu
C. Psittacosis ✅
D. Cholera
A. Typhoid
B. Bird flu
C. Psittacosis ✅
D. Cholera
47. The ability of the immune system to recognize self-antigens versus non-self-antigen is an example of:
A. Specific immunity
B. Humoral immunity
C. Cell mediated immunity
D. Tolerance ✅
A. Specific immunity
B. Humoral immunity
C. Cell mediated immunity
D. Tolerance ✅
48. The coagulase test is used to differentiate between Staphylococcus aureus from:
A. Streptococci
B. Micrococci
C. Enterococci
D. other staphylococci ✅
A. Streptococci
B. Micrococci
C. Enterococci
D. other staphylococci ✅
49. All are antigen-antibody interaction in living host EXCEPT:
A. Neutralization
B. Precipitation ✅
C. Opsonization
D. Agglutination
A. Neutralization
B. Precipitation ✅
C. Opsonization
D. Agglutination
50. Which of the following is type of leukocytes are included in agranulocytes?
A. Neutrophils
B. Basophils
C. Monocytes ✅
D. Eosinophils
A. Neutrophils
B. Basophils
C. Monocytes ✅
D. Eosinophils
51. Which one is NOT protective mechanism of body:
A. Fever
B. Necrosis ✅
C. Phagocytosis
D. Inflammation
A. Fever
B. Necrosis ✅
C. Phagocytosis
D. Inflammation
52. Bioterrorism microbial agents are classified based upon:
A. Pathogenicity
B. Spread
C. Availability
D. Both “A” and “B” ✅
A. Pathogenicity
B. Spread
C. Availability
D. Both “A” and “B” ✅
53. Which one of the following immunoglobulins can cross the blood placental barrier?
A. Ig G ✅
B. Ig M
C. Ig A
D. Ig D
A. Ig G ✅
B. Ig M
C. Ig A
D. Ig D
54. Hematopoietic stem cells are precursor cells for all of the following EXCEPT:
A. Lymphocytes
B. Monocytes
C. Erythrocytes
D. Vascular smooth muscle cells ✅
A. Lymphocytes
B. Monocytes
C. Erythrocytes
D. Vascular smooth muscle cells ✅
55. Macrophages present in liver are called:
A. microglial cells
B. alveolar macrophages
C. Kupffer cells ✅
D. wondering macrophages
A. microglial cells
B. alveolar macrophages
C. Kupffer cells ✅
D. wondering macrophages
56. Antibiotic penicillin was introduced by:
A. Pasteur
B. Fleming ✅
C. Jenner
D. Lister
A. Pasteur
B. Fleming ✅
C. Jenner
D. Lister
57. Prokaryotic cell lacks:
A. DNA
B. Ribosomes
C. Mitochondria ✅
D. Plasma membrane
A. DNA
B. Ribosomes
C. Mitochondria ✅
D. Plasma membrane
58. Immunity against yellow fever in new born is an example of:
A. Active naturally acquired
B. passive artificially acquired
C. passive naturally acquired ✅
D. artificial immunity
A. Active naturally acquired
B. passive artificially acquired
C. passive naturally acquired ✅
D. artificial immunity
59. All structures are external to cell wall EXCEPT:
A. Glycocalyx
B. Flagella
C. Pilli
D. Spores ✅
A. Glycocalyx
B. Flagella
C. Pilli
D. Spores ✅
60. A typical bacterial cell has only _____ volume of a typical eukaryotic cell.
A. 1/10
B. 1/100
C. 1/1000 ✅
D. 1/10000
A. 1/10
B. 1/100
C. 1/1000 ✅
D. 1/10000
61. PCR reaction includes all, EXCEPT:
A. DNA ligase ✅
B. four DNTPs
C. DNA template
D. DNA polymerase
A. DNA ligase ✅
B. four DNTPs
C. DNA template
D. DNA polymerase
62. If disease is endemic, prevalence equals to:
A. C x I
B. I x D
C. P x D
D. C x D ✅
A. C x I
B. I x D
C. P x D
D. C x D ✅
63. Southern hybridization is used to identify:
A. A specific protein
B. A specific RNA seq
C. A specific DNA sequence ✅
D. Both “A” and “B”
A. A specific protein
B. A specific RNA seq
C. A specific DNA sequence ✅
D. Both “A” and “B”
64. All of the following bacteria are members of family Enterobacteriaceae EXCEPT:
A. E. coli
B. Shigella
C. Staphylococcus ✅
D. Salmonella
A. E. coli
B. Shigella
C. Staphylococcus ✅
D. Salmonella
65. A library of DNA fragments results from the use of:
A. Viruses
B. Restriction endonucleases ✅
C. DNA ligases
D. Plasmids
A. Viruses
B. Restriction endonucleases ✅
C. DNA ligases
D. Plasmids
66. Swarming growth is the characteristic of Gram-negative bacteria known as:
A. Clostridium
B. Proteus
C. Pasteurella
D. Pseudomonas ✅
A. Clostridium
B. Proteus
C. Pasteurella
D. Pseudomonas ✅
67. Mesophilic bacteria CANNOT grow at temperature:
A. 16oC ✅
B. 25oC
C. 35oC
D. 38oC
A. 16oC ✅
B. 25oC
C. 35oC
D. 38oC
68. Facultative anaerobic bacteria grow in presence of:
A. only O2
B. O2 and also CO2 ✅
C. only CO2
D. N2
A. only O2
B. O2 and also CO2 ✅
C. only CO2
D. N2
69. Mannitol salt agar is an example of:
A. Selective medium ✅
B. Differential medium
C. Both “A” and “B”
D. Enrichment medium
A. Selective medium ✅
B. Differential medium
C. Both “A” and “B”
D. Enrichment medium
70. Translation occurs in:
A. Nucleus
B. Cytoplasm
C. Ribosomes ✅
D. Both “A” and “B”
A. Nucleus
B. Cytoplasm
C. Ribosomes ✅
D. Both “A” and “B”
71. An intron is found in:
A. DNA
B. RNA
C. mRNA ✅
D. tRNA
A. DNA
B. RNA
C. mRNA ✅
D. tRNA
72. Signal responsible for the end of transcription is:
A. Stop codon
B. RNA polymerase run out
C. End of DNA chain
D. Terminator ✅
A. Stop codon
B. RNA polymerase run out
C. End of DNA chain
D. Terminator ✅
73. Plasmids are inserted in bacterial cell from environment:
A. Transformation ✅
B. DNA ligase
C. Transfection
D. Transduction
A. Transformation ✅
B. DNA ligase
C. Transfection
D. Transduction
74. Which of following could NOT be a portal of entry?
A. Meninges ✅
B. Skin
C. Placenta
D. Small intestine
A. Meninges ✅
B. Skin
C. Placenta
D. Small intestine
75. Highly communicable pathogen, especially via direct contact is known as:
A. Zoonotic
B. Contagious ✅
C. Nosocomial
D. Communicable
A. Zoonotic
B. Contagious ✅
C. Nosocomial
D. Communicable
76. Motility of the bacteria can be observed by:
A. Hanging drop method
B. Soft agar method
C. Both “A” and “B” ✅
D. Pour plate method
A. Hanging drop method
B. Soft agar method
C. Both “A” and “B” ✅
D. Pour plate method
77. O157:H7 is pathogenic type of:
A. Salmonella typhi
B. E. coli ✅
C. S. aureus
D. Streptococcus
A. Salmonella typhi
B. E. coli ✅
C. S. aureus
D. Streptococcus
78. All of the following bacteria are non-spore forming bacteria EXCEPT:
A. E. coli
B. Clostridium ✅
C. Streptococcus
D. Leptospira
A. E. coli
B. Clostridium ✅
C. Streptococcus
D. Leptospira
79. The ability of Microscope to distinguish two objects into two separate objects, is called:
A. Magnification power
B. Wave length
C. Resolving power ✅
D. None of these
A. Magnification power
B. Wave length
C. Resolving power ✅
D. None of these
80. A sudden outbreak of disease in which number of cases increase beyond expected trends is known as:
A. Endemic
B. Epidemic ✅
C. Sporadic
D. Pandemic
A. Endemic
B. Epidemic ✅
C. Sporadic
D. Pandemic
81. Serum is collected from____________ blood.
A. Heparinized
B. Unclotted
C. Clotted ✅
D. All of these
A. Heparinized
B. Unclotted
C. Clotted ✅
D. All of these
82. Amboceptors are Abs raised against RBCs of:
A. Sheep
B. Cow
C. Goat
D. Horse ✅
A. Sheep
B. Cow
C. Goat
D. Horse ✅
83. GET buffer in plasmid isolation of bacteria contains:
A. Glucose
B. EDTA
C. Tris
D. All of these ✅
A. Glucose
B. EDTA
C. Tris
D. All of these ✅
84. Majority of the antigens are:
A. Protein ✅
B. Nucleic acid
C. Lipids
D. Carbohydrates
A. Protein ✅
B. Nucleic acid
C. Lipids
D. Carbohydrates
85. RNAi’ stands for which of the following:
A. RNA inducer
B. RNA insertion
C. RNA interference ✅
D. RNA intron
A. RNA inducer
B. RNA insertion
C. RNA interference ✅
D. RNA intron
86. The botulism intoxication occurs due to:
A. An enterotoxin
B. A neurotoxin ✅
C. A mycotoxin
D. All of these
A. An enterotoxin
B. A neurotoxin ✅
C. A mycotoxin
D. All of these
87. An animal that only acts as short-term transmitter:
A. Passive carrier
B. Mechanical carrier ✅
C. Biological carrier
D. Asymptomatic carrier
A. Passive carrier
B. Mechanical carrier ✅
C. Biological carrier
D. Asymptomatic carrier
88. Adenine and guanine are example of which class of nitrogen base:
A. Large
B. Pyrimidines
C. Small
D. Purines ✅
A. Large
B. Pyrimidines
C. Small
D. Purines ✅
89. Which of the following is not a function of capsule?
A. Attachment
B. Motility ✅
C. Biofilm
D. Used as nutrition
A. Attachment
B. Motility ✅
C. Biofilm
D. Used as nutrition
90. Whiff test is used for the diagnosis of:
A. Entamoeba
B. Giardia
C. E. coli
D. Trichomonas ✅
A. Entamoeba
B. Giardia
C. E. coli
D. Trichomonas ✅
91. _____is Gram positive rod & spore forming bacteria.
A. Pseudomonas
B. Staphylococcus
C. Salmonella
D. Bacillus ✅
A. Pseudomonas
B. Staphylococcus
C. Salmonella
D. Bacillus ✅
92. Which of the following vaccine is recommended for pregnant women?
A. Tetanus ✅
B. Tuberculosis
C. AIDS
D. Poliomyelitis
A. Tetanus ✅
B. Tuberculosis
C. AIDS
D. Poliomyelitis
93. Natural competence was first time described in:
A. E. coli
B. Streptococcus
C. Staphylococcus
D. Bacillus ✅
A. E. coli
B. Streptococcus
C. Staphylococcus
D. Bacillus ✅
94. In genomic DNA isolation, TE buffer functions as:
A. Block endonucleases
B. Maintain pH
C. Denature protein
D. Both “A” and “B” ✅
A. Block endonucleases
B. Maintain pH
C. Denature protein
D. Both “A” and “B” ✅
95. An example of non-communicable disease is:
A. Measles
B. Tuberculosis
C. Leprosy
D. Tetanus ✅
A. Measles
B. Tuberculosis
C. Leprosy
D. Tetanus ✅
96. E. coli O157:H7 produces ______.
A. Colon toxin
B. Neurotoxin
C. Exotoxin
D. Shiga toxin ✅
A. Colon toxin
B. Neurotoxin
C. Exotoxin
D. Shiga toxin ✅
97. Treatment with which salt gives properties of competency to bacterial cells?
A. NaCl
B. HgCl
C. NaHCO3
D. CaCl2 ✅
A. NaCl
B. HgCl
C. NaHCO3
D. CaCl2 ✅
98. Lyophilization means:
A. Sterilization
B. Burning to ashes
C. Exposure to formation
D. Freeze-drying ✅
A. Sterilization
B. Burning to ashes
C. Exposure to formation
D. Freeze-drying ✅
99. ________ is NOT an example of inflammation?
A. Pain
B. Sweating ✅
C. Heat
D. Swelling
A. Pain
B. Sweating ✅
C. Heat
D. Swelling
100. Typhoid is usually diagnosed by:
A. Typhidot test
B. Widal test
C. Precipitation test
D. Both “A” and “B” ✅
A. Typhidot test
B. Widal test
C. Precipitation test
D. Both “A” and “B” ✅
