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