Free General Microbiology MCQs with Answers
14 General Microbiology MCQs from Microbiology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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14 questions
- A. Eosin stain
- B. Haemotoxin stain
- C. Ninhydrin stain
- D. Blue stain
Explanation: Ninhydrin reacts with amino groups and produces a coloured compound, making the marked or wetted region on filter paper easier to see.
Correct answer: Ninhydrin stain- A. -20°C to -7°C
- B. -7°C to + 20°C
- C. 25°C to 40°C
- D. 55°C to 80°C
Explanation: Mesophiles grow best at moderate temperatures, commonly about 25°C to 40°C, with many human pathogens having an optimum near 37°C.
Correct answer: 25°C to 40°C- A. 10%
- B. 2%
- C. 5%
- D. 15%
Explanation: Agar is usually used at about 1.5% to 2% to solidify culture media while still permitting diffusion of nutrients and growth of colonies.
Correct answer: 2%- A. Introduction of complex media
- B. Discovery of Rabies Vaccine
- C. Discovery of M. Tuberculosis
- D. Disproved spontaneous regression theory
Explanation: Louis Pasteur developed the rabies vaccine, introduced complex culture media, and disproved spontaneous generation.
Correct answer: Discovery of M. Tuberculosis- A. Internal structures are differentiated in living cells
- B. Internal structures are differentiated in dead cells
- C. Internal metabolic activities can be observed
- D. External capsule formation can be observed
Explanation: Phase-contrast microscopy converts small differences in refractive index into contrast, allowing internal structures of living, unstained…
Correct answer: Internal structures are differentiated in living cells- A. Wd miller
- B. Leumenhoek
- C. Robertson
- D. Socranci
Explanation: Antonie van Leeuwenhoek first described oral microorganisms as tiny ‘animalcules’ after observing dental plaque microscopically.
Correct answer: Leumenhoek- A. Different refractive indices of object
- B. Different reflective indices of object
- C. Light scattering
- D. Light attenuation
Explanation: Phase-contrast microscopy converts differences in refractive index and thickness into visible differences in brightness and contrast.
Correct answer: Different refractive indices of object- A. dna
- B. Ribosome
- C. Mitochondria
- D. Cell wall
Explanation: Bacteria are prokaryotes, so they lack membrane-bound organelles such as mitochondria.
Correct answer: Mitochondria- A. Lag phase
- B. Log phase
- C. Stationary phase
- D. Decline phase
Explanation: Sporulation usually begins in the stationary phase when nutrients are depleted and environmental stress increases.
Correct answer: Stationary phase- A. in the presence of oxygen
- B. in the presence of nitrogen
- C. in the absence of oxygen
- D. differential media
Explanation: Anaerobic bacteria grow without oxygen because oxygen is toxic to them or cannot be used for their metabolism.
Correct answer: in the absence of oxygen- A. Treponema pallidum
- B. Mycobacterium leprae
- C. N. gonorrhoeae
- D. None of the above
Explanation: None of these organisms fulfils every classical Koch postulate: Treponema pallidum and Mycobacterium leprae cannot be routinely grown in…
Correct answer: None of the above- A. Unicellular
- B. Free living
- C. Having either DNA or RNA
- D. Cell wall containing muramic acid
Explanation: Bacteria are cellular organisms containing both DNA and RNA, whereas viruses contain either DNA or RNA as their genetic material.
Correct answer: Having either DNA or RNA- A. Psychrophiles
- B. Mesophiles
- C. Cryophiles
- D. Thermophiles
Explanation: Most pathogenic bacteria are mesophiles because they grow best at moderate temperatures, typically around 20–45°C, with human pathogens…
Correct answer: Mesophiles- A. Lag phase
- B. Death phase
- C. Stationary phase
- D. Logarithmic phase
Explanation: The logarithmic phase provides actively dividing, physiologically uniform cells, so it is best for studying consistent morphology…
Correct answer: Logarithmic phaseGeneral Microbiology MCQs: common questions
Are these General Microbiology MCQs free?
Yes. All General Microbiology MCQs from Microbiology are free on TestUstad, with unlimited attempts and no account needed. Nothing on this page is a sample or a trial.
How many General Microbiology MCQs are on this page?
There are 14 General Microbiology MCQs in the Microbiology bank, shown 20 to a page with the correct answer and an explanation on each.
Does every General Microbiology MCQ have an explanation?
Yes. Each General Microbiology question shows the correct option and a written explanation of why it is correct, so a wrong answer teaches you something rather than just being marked wrong.
Can I take a timed General Microbiology test?
Yes. The practice button on this page starts a free General Microbiology test drawn from the Microbiology bank. It marks each answer instantly, gives you a score at the end, and can be retaken as many times as you like.