BSc First Year (Sem 1 & 2) Microbiology – Daily Revision MCQ (English Medium)
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Who was the first to observe and describe microorganisms, which he called 'animalcules', using his own simple microscopes?
Chapter 1: History and Scope of Microbiology
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Answer: C. Antonie van Leeuwenhoek
Leeuwenhoek (17th century) ground his own lenses and first described bacteria and protozoa as 'animalcules'.The ribosomes found in the cytoplasm of prokaryotic cells are of which type?
Chapter 2: Prokaryotic and Eukaryotic Cells
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Answer: D. 70S
Prokaryotes have 70S ribosomes (50S + 30S subunits); eukaryotic cytoplasm has 80S ribosomes.Teichoic acids are a characteristic component of the cell wall of:
Chapter 6: Bacterial Cell Wall: Gram-positive and Gram-negative
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Answer: B. Gram-positive bacteria
Gram-positive walls have a thick peptidoglycan layer with teichoic acids; Gram-negative walls have a thin peptidoglycan layer and an outer membrane with LPS.In Gram staining, which dye is used as the primary stain?
Chapter 8: Staining Techniques
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Answer: C. Crystal violet
Crystal violet is the primary stain, iodine the mordant, alcohol the decolouriser and safranin the counterstain.What is the standard condition for sterilization in an autoclave?
Chapter 9: Sterilization and Disinfection
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Answer: A. 121°C at 15 psi (lb/inch²) for 15 minutes
Steam under 15 psi pressure reaches 121°C and kills even endospores in about 15 minutes; 160°C/2 h is the hot-air oven and 63°C/30 min is pasteurization.Agar, the solidifying agent used in culture media, is obtained from:
Chapter 12: Culture Media and Pure Culture
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Answer: A. red algae
Agar is a polysaccharide extracted from marine red algae such as Gelidium and Gracilaria; most microbes cannot digest it.In a bacterial growth curve, the phase in which cells divide at a constant, maximum rate and their number doubles every generation is the:
Chapter 13: Bacterial Growth
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Answer: C. log (exponential) phase
In the log phase cells divide by binary fission at a constant rate, so the logarithm of cell number rises in a straight line.Who proposed the five-kingdom classification (Monera, Protista, Fungi, Plantae, Animalia)?
Chapter 14: Classification of Microorganisms
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Answer: D. R. H. Whittaker
Whittaker (1969) proposed five kingdoms; Linnaeus gave two kingdoms, Haeckel added Protista, and Woese proposed the three domains.Mycoplasma differs from other bacteria mainly because it:
Chapter 15: Rickettsia, Chlamydia and Mycoplasma
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Answer: A. has no cell wall
Mycoplasmas lack a cell wall (only a sterol-containing membrane), so they are pleomorphic and resistant to penicillin.Viruses that infect bacteria are called:
Chapter 18: Introduction to Viruses
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Answer: C. bacteriophages
Bacteriophages (phages), such as T4 of E. coli, infect bacteria; viroids are naked RNA plant pathogens and prions are infectious proteins.
BSc First Year (Sem 1 & 2): MCQ in other subjects
All questions are written by PadhaiNotes in our own words from the common syllabus of Maharashtra universities (NEP). Your own university's syllabus may differ a little.