Microbiology - MCQ Practice Questions

A laboratory identifies a virus with single-stranded RNA genome that must first be transcribed to mRNA before protein synthesis. What is this virus classified as?

In a viral outbreak investigation, electron microscopy reveals enveloped, pleomorphic particles (80-120 nm) with crown-like spike projections. Which family is most consistent?

A Gram-negative bacterium shows resistance to multiple antibiotics including cephalosporins. The presence of which enzymatic mechanism is most likely responsible?

A bacterium isolated from a urinary tract infection produces urease enzyme, enabling it to raise urine pH and form struvite crystals. Which organism is most likely?

In viral replication cycles, retroviruses are unique in requiring which enzyme for reverse transcription of their RNA genome?

A patient with severe meningitis has CSF culture yielding Gram-positive cocci in chains with positive optochin test and bile solubility. What is the organism?

Which bacteriophage classification system categorizes viruses based on nucleic acid type and presence/absence of envelopes?

A patient with diabetic foot ulcer yields Vibrio vulnificus from wound culture. Which environmental niche is this halophilic organism primarily associated with?

In bacterial conjugation, which plasmid type can transfer genes between different bacterial species through direct cell-to-cell contact?

Which of the following is a characteristic feature of SARS-CoV-2 that contributes to its high transmissibility?

A patient presents with atypical pneumonia. Which bacterial pathogen should be considered if Gram staining shows no organism but PCR is positive?

Which viral replication strategy involves reverse transcription of RNA to DNA?

Which bacterial structure mediates horizontal gene transfer through direct cell-to-cell contact?

A diagnostic lab suspects tuberculosis. Which staining technique is most appropriate for detecting Mycobacterium tuberculosis?

Which bacterial toxin directly inhibits protein synthesis by modifying EF-2 in host cells?

In viral latency, which herpesvirus establishes latency in sensory nerve ganglia?

Which viral enzyme is responsible for integrating retroviral DNA into the host genome?

A nosocomial outbreak of antibiotic-resistant Acinetobacter baumannii is investigated. Which transmission route is most likely?

A bacterial strain shows resistance to multiple antibiotics. Which genetic element is most likely responsible?

Which bacterial species is known to produce lipopolysaccharide (LPS) as an endotoxin?