100 High-Yield Microbiology MCQs
For Nursing & Medical Students – Answers Included for Self-Practice &
Assessment
Instructions: Choose the correct option. Answer key is at the bottom for self-
assessment.
1. The study of microorganisms is called:
a) Zoology b) Botany c) Microbiology d) Ecology
2. The smallest living organisms are:
a) Viruses b) Bacteria c) Protozoa d) Fungi
3. The father of microbiology is:
a) Koch b) Pasteur c) Leeuwenhoek d) Jenner
4. Bacteria reproduce mainly by:
a) Budding b) Binary fission c) Fragmentation d) Spore formation
5. Gram-positive bacteria appear:
a) Red b) Pink c) Purple d) Colorless
6. Gram-negative bacteria have:
a) Thick peptidoglycan b) Thin peptidoglycan c) No cell wall d) Only
protein coat
7. The cell wall of fungi contains:
a) Cellulose b) Chitin c) Pectin d) Lignin
8. Mycoplasma lacks:
a) DNA b) Cell membrane c) Cell wall d) Ribosomes
9. Example of acid-fast bacteria:
a) S. aureus b) E. coli c) Mycobacterium tuberculosis d) Streptococcus
pyogenes
10.Viruses replicate in:
a) Soil b) Food c) Living cells d) Water
11.Example of dimorphic fungi:
a) Candida b) Aspergillus c) Histoplasma d) Penicillium
,12.Bacterial ribosomes are:
a) 60S b) 80S c) 70S d) 30S
13.Endotoxin is found in:
a) Gram-positive b) Gram-negative c) Fungi d) Viruses
14.Prions cause disease in:
a) Plants b) Animals c) Bacteria d) Protozoa
15.Sterilization destroys:
a) Only bacteria b) Only viruses c) Spores d) Only fungi
16.Disinfection kills:
a) All microbes b) Spores c) Pathogens d) Prions
17.Best method for sterilizing heat-sensitive items:
a) Autoclave b) Dry heat oven c) Filtration d) Flaming
18.The clear zone around antibiotic disc is:
a) Growth zone b) Culture zone c) Hemolytic zone d) Zone of inhibition
19.Koch’s postulates are used to:
a) Classify microbes b) Identify pathogens c) Prepare culture media d) Test
antibiotics
20.Flagella help in:
a) Respiration b) Motility c) Reproduction d) Protein synthesis
21.The most common cause of food poisoning is:
a) Salmonella b) Staphylococcus aureus c) Shigella d) Vibrio cholerae
22.Diphtheria is caused by:
a) Corynebacterium diphtheriae b) Clostridium tetani c) Mycoplasma d)
Neisseria
23.Whooping cough organism:
a) Bordetella pertussis b) H. influenzae c) Klebsiella d) E. coli
24.Lancefield classification is used for:
a) Staphylococci b) Streptococci c) E. coli d) Bacillus
25.Chocolate agar is used for:
a) Vibrio b) Neisseria c) Staph d) Clostridium
,26.Alpha hemolysis produces:
a) Greenish zone b) Clear zone c) No change d) Black zone
27.Tetanus is caused by:
a) C. welchii b) C. tetani c) C. botulinum d) C. perfringens
28.Botulism toxin causes:
a) Spastic paralysis b) Flaccid paralysis c) Fever d) Rash
29.Typhoid fever organism:
a) S. typhi b) S. aureus c) P. aeruginosa d) Shigella
30.Cholera causes:
a) Bloody diarrhea b) Rice-water stool c) Constipation d) Vomiting only
31.Primary tuberculosis affects:
a) Brain b) Bones c) Lungs d) Skin
32.Leprosy is caused by:
a) M. leprae b) M. tuberculosis c) M. kansasii d) M. avium
33.UTI most common organism:
a) Candida b) E. coli c) Staph d) Klebsiella
34.Gas gangrene:
a) C. botulinum b) C. perfringens c) C. tetani d) C. difficile
35.Anthrax organism:
a) Bacillus anthracis b) Yersinia c) Pasteurella d) Listeria
36.Capsule is made of:
a) Protein b) Polysaccharide c) Lipid d) Peptidoglycan
37.Pili help in:
a) Movement b) Conjugation c) Respiration d) Sporulation
38.Bacterial spores resist:
a) Heat b) Drying c) Chemicals d) All of the above
39.Optimum temperature for most pathogens:
a) 25°C b) 37°C c) 15°C d) 45°C
,40.Syphilis is caused by:
a) Borrelia b) Treponema pallidum c) Leptospira d) Rickettsia
41.Lyme disease organism:
a) Borrelia burgdorferi b) S. aureus c) Shigella d) Vibrio
42.Rickettsia transmission:
a) Food b) Tick c) Water d) Air
43.Most common pneumonia bacteria:
a) S. pneumoniae b) Mycoplasma c) Legionella d) Klebsiella
44.H. pylori causes:
a) Liver cirrhosis b) Gastric ulcer c) Pancreatitis d) Malaria
45.Meningitis in infants caused by:
a) H. influenzae b) S. pneumoniae c) Neisseria d) All
46.Neonatal sepsis:
a) Group B Streptococcus b) Group A c) E. coli only d) Staph
47.Gonorrhea organism:
a) Chlamydia b) Treponema c) Neisseria gonorrhoeae d) Candida
48.Biofilms are produced by:
a) S. epidermidis b) Vibrio c) Salmonella d) Shigella
49.Catalase test differentiates:
a) Staph + and Strep – b) Gram + and – c) Bacilli and cocci d) Aerobes and
anaerobes
50.Coagulase test identifies:
a) S. epidermidis b) S. aureus c) S. pneumoniae d) Enterococcus
51.HIV infects:
a) CD8 cells b) CD4 cells c) RBC d) Macrophage only
52.Hepatitis B transmission is:
a) Fecal-oral b) Water c) Blood d) Food
53.Chickenpox virus:
a) HSV-1 b) HSV-2 c) VZV d) CMV
, 54.Measles symptom:
a) Koplik spots b) Bull neck c) Lockjaw d) Night sweats
55.Mumps affects:
a) Brain b) Parotid gland c) Throat d) Liver
56.Rabies virus is:
a) DNA virus b) RNA virus c) Fungus d) Bacteria
57.Polio virus infects:
a) Bone b) Liver c) Motor neurons d) Lungs
58.COVID-19 virus is:
a) Retrovirus b) Coronavirus c) Adenovirus d) Poxvirus
59.Influenza spreads by:
a) Water b) Air droplets c) Fomite only d) Sexual contact
60.Hepatitis A spreads by:
a) Blood b) Fecal-oral c) Sexual d) Respiratory
61.CMV commonly affects:
a) Immunocompromised b) Healthy c) Neonates only d) Elderly only
62.HPV causes:
a) Lung cancer b) Cervical cancer c) Liver cancer d) Skin cancer
63.Dengue vector:
a) Anopheles b) Aedes c) Culex d) Sandfly
64.Zika virus causes:
a) Microcephaly b) Lung fibrosis c) Renal failure d) Diabetes
65.Ebola spreads by:
a) Air b) Direct contact c) Water d) Soil
66.Rotavirus affects:
a) Liver b) Intestines c) Lungs d) Heart
67.Hepatitis C transmission:
a) Water b) Blood c) Air d) Food
For Nursing & Medical Students – Answers Included for Self-Practice &
Assessment
Instructions: Choose the correct option. Answer key is at the bottom for self-
assessment.
1. The study of microorganisms is called:
a) Zoology b) Botany c) Microbiology d) Ecology
2. The smallest living organisms are:
a) Viruses b) Bacteria c) Protozoa d) Fungi
3. The father of microbiology is:
a) Koch b) Pasteur c) Leeuwenhoek d) Jenner
4. Bacteria reproduce mainly by:
a) Budding b) Binary fission c) Fragmentation d) Spore formation
5. Gram-positive bacteria appear:
a) Red b) Pink c) Purple d) Colorless
6. Gram-negative bacteria have:
a) Thick peptidoglycan b) Thin peptidoglycan c) No cell wall d) Only
protein coat
7. The cell wall of fungi contains:
a) Cellulose b) Chitin c) Pectin d) Lignin
8. Mycoplasma lacks:
a) DNA b) Cell membrane c) Cell wall d) Ribosomes
9. Example of acid-fast bacteria:
a) S. aureus b) E. coli c) Mycobacterium tuberculosis d) Streptococcus
pyogenes
10.Viruses replicate in:
a) Soil b) Food c) Living cells d) Water
11.Example of dimorphic fungi:
a) Candida b) Aspergillus c) Histoplasma d) Penicillium
,12.Bacterial ribosomes are:
a) 60S b) 80S c) 70S d) 30S
13.Endotoxin is found in:
a) Gram-positive b) Gram-negative c) Fungi d) Viruses
14.Prions cause disease in:
a) Plants b) Animals c) Bacteria d) Protozoa
15.Sterilization destroys:
a) Only bacteria b) Only viruses c) Spores d) Only fungi
16.Disinfection kills:
a) All microbes b) Spores c) Pathogens d) Prions
17.Best method for sterilizing heat-sensitive items:
a) Autoclave b) Dry heat oven c) Filtration d) Flaming
18.The clear zone around antibiotic disc is:
a) Growth zone b) Culture zone c) Hemolytic zone d) Zone of inhibition
19.Koch’s postulates are used to:
a) Classify microbes b) Identify pathogens c) Prepare culture media d) Test
antibiotics
20.Flagella help in:
a) Respiration b) Motility c) Reproduction d) Protein synthesis
21.The most common cause of food poisoning is:
a) Salmonella b) Staphylococcus aureus c) Shigella d) Vibrio cholerae
22.Diphtheria is caused by:
a) Corynebacterium diphtheriae b) Clostridium tetani c) Mycoplasma d)
Neisseria
23.Whooping cough organism:
a) Bordetella pertussis b) H. influenzae c) Klebsiella d) E. coli
24.Lancefield classification is used for:
a) Staphylococci b) Streptococci c) E. coli d) Bacillus
25.Chocolate agar is used for:
a) Vibrio b) Neisseria c) Staph d) Clostridium
,26.Alpha hemolysis produces:
a) Greenish zone b) Clear zone c) No change d) Black zone
27.Tetanus is caused by:
a) C. welchii b) C. tetani c) C. botulinum d) C. perfringens
28.Botulism toxin causes:
a) Spastic paralysis b) Flaccid paralysis c) Fever d) Rash
29.Typhoid fever organism:
a) S. typhi b) S. aureus c) P. aeruginosa d) Shigella
30.Cholera causes:
a) Bloody diarrhea b) Rice-water stool c) Constipation d) Vomiting only
31.Primary tuberculosis affects:
a) Brain b) Bones c) Lungs d) Skin
32.Leprosy is caused by:
a) M. leprae b) M. tuberculosis c) M. kansasii d) M. avium
33.UTI most common organism:
a) Candida b) E. coli c) Staph d) Klebsiella
34.Gas gangrene:
a) C. botulinum b) C. perfringens c) C. tetani d) C. difficile
35.Anthrax organism:
a) Bacillus anthracis b) Yersinia c) Pasteurella d) Listeria
36.Capsule is made of:
a) Protein b) Polysaccharide c) Lipid d) Peptidoglycan
37.Pili help in:
a) Movement b) Conjugation c) Respiration d) Sporulation
38.Bacterial spores resist:
a) Heat b) Drying c) Chemicals d) All of the above
39.Optimum temperature for most pathogens:
a) 25°C b) 37°C c) 15°C d) 45°C
,40.Syphilis is caused by:
a) Borrelia b) Treponema pallidum c) Leptospira d) Rickettsia
41.Lyme disease organism:
a) Borrelia burgdorferi b) S. aureus c) Shigella d) Vibrio
42.Rickettsia transmission:
a) Food b) Tick c) Water d) Air
43.Most common pneumonia bacteria:
a) S. pneumoniae b) Mycoplasma c) Legionella d) Klebsiella
44.H. pylori causes:
a) Liver cirrhosis b) Gastric ulcer c) Pancreatitis d) Malaria
45.Meningitis in infants caused by:
a) H. influenzae b) S. pneumoniae c) Neisseria d) All
46.Neonatal sepsis:
a) Group B Streptococcus b) Group A c) E. coli only d) Staph
47.Gonorrhea organism:
a) Chlamydia b) Treponema c) Neisseria gonorrhoeae d) Candida
48.Biofilms are produced by:
a) S. epidermidis b) Vibrio c) Salmonella d) Shigella
49.Catalase test differentiates:
a) Staph + and Strep – b) Gram + and – c) Bacilli and cocci d) Aerobes and
anaerobes
50.Coagulase test identifies:
a) S. epidermidis b) S. aureus c) S. pneumoniae d) Enterococcus
51.HIV infects:
a) CD8 cells b) CD4 cells c) RBC d) Macrophage only
52.Hepatitis B transmission is:
a) Fecal-oral b) Water c) Blood d) Food
53.Chickenpox virus:
a) HSV-1 b) HSV-2 c) VZV d) CMV
, 54.Measles symptom:
a) Koplik spots b) Bull neck c) Lockjaw d) Night sweats
55.Mumps affects:
a) Brain b) Parotid gland c) Throat d) Liver
56.Rabies virus is:
a) DNA virus b) RNA virus c) Fungus d) Bacteria
57.Polio virus infects:
a) Bone b) Liver c) Motor neurons d) Lungs
58.COVID-19 virus is:
a) Retrovirus b) Coronavirus c) Adenovirus d) Poxvirus
59.Influenza spreads by:
a) Water b) Air droplets c) Fomite only d) Sexual contact
60.Hepatitis A spreads by:
a) Blood b) Fecal-oral c) Sexual d) Respiratory
61.CMV commonly affects:
a) Immunocompromised b) Healthy c) Neonates only d) Elderly only
62.HPV causes:
a) Lung cancer b) Cervical cancer c) Liver cancer d) Skin cancer
63.Dengue vector:
a) Anopheles b) Aedes c) Culex d) Sandfly
64.Zika virus causes:
a) Microcephaly b) Lung fibrosis c) Renal failure d) Diabetes
65.Ebola spreads by:
a) Air b) Direct contact c) Water d) Soil
66.Rotavirus affects:
a) Liver b) Intestines c) Lungs d) Heart
67.Hepatitis C transmission:
a) Water b) Blood c) Air d) Food
