Microbiology MCQs (Quiz 8) Posted on June 8, 2026Author agropublishers 0 1. Why is agar more suitable than gelatin for preparing solid culture media? Agar contains antimicrobial compounds Agar is a better nutrient source Agar remains solid at incubation temperatures and is not easily degraded by bacteria Agar is cheaper than gelatin 2. Joseph Lister concluded that surgical infections were caused by _________________ Spontaneous generation Bad air alone Microorganisms entering wounds Changes in body temperature 3. Many bacteria cannot use agar as a food source because they ______________ Cannot absorb carbohydrates Lack cell walls Lack ribosomes Lack enzymes capable of degrading agar 4. Alcohol is widely used as an intermediate-level disinfectant because it _____________ Sterilizes culture media Replaces autoclaving Kills many vegetative microorganisms but not all spores Destroys all spores 5. A microbiologist examining pigment production by bacterial colonies would benefit from agar’s ____________ Nutritional value Transparency Antimicrobial activity High melting point 6. _________________ ensures complete elimination of all microorganisms, including spores Sterilization Antisepsis Sanitization Disinfection 7. In microbiological studies, phenol was one of the earliest chemicals used as a _____________ Growth medium component Disinfectant Sterilizing agent Staining reagent 8. Eukaryotic 80S ribosomes consist of ________________ 20S and 60S subunits 30S and 60S subunits 30S and 50S subunits 40S and 60S subunits 9. Agar, a jelly-like substance used to solidify microbiological media, is classified as a _______________ Nucleic acid Polysaccharide Protein Lipid 10. The concept that microorganisms cause putrefaction and wound infections led Joseph Lister to introduce ____________________ Aseptic culturing Vaccination Antiseptic surgery Antibiotic therapy Loading … Question 1 of 10
