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