Microbiology MCQs (Quiz 9) Posted on June 8, 2026June 10, 2026Author agropublishers 0 1. Agar exhibits thermal hysteresis because _______________ It contains proteins It changes color during heating Bacteria degrade it Its melting temperature is much higher than its solidification temperature 2. The primary lethal effect of UV radiation on microorganisms is the formation of ________ in DNA ATP molecules Peptidoglycan cross-links Disulfide bonds Thymine dimers 3. Which microorganism contains 70S ribosomes? Yeast Paramecium Escherichia coli Amoeba 4. ______________ radiation is most commonly used for sterilizing disposable syringes, catheters, and surgical gloves Infrared radiation Ultraviolet radiation Microwaves Gamma radiation 5. Chlorine is most widely used in public health for the disinfection of _____________ Hospital floors Surgical instruments Water Culture media 6. Most pathogenic microorganisms obtain both energy and carbon from ______________ Organic compounds Inorganic chemicals and CO₂ Sunlight and organic compounds Sunlight and CO₂ 7. In microbiology, UV radiation is mainly used for ___________ Surface disinfection Sterilizing surgical instruments Deep tissue sterilization Sterilizing culture media 8. Which principle is involved in sterilization by membrane filtration? Heat destruction Physical separation Chemical inactivation Radiation damage 9. The germicidal effectiveness of Ultraviolet (UV) radiation is greatest at approximately __________ 254 nm 900 nm 700 nm 500 nm 10. Joseph Lister’s introduction of antiseptic surgery significantly reduced ____________________ Viral infections Tuberculosis transmission Fermentation in food Post-operative infections and mortality Loading … Question 1 of 10 Microbiology MCQs (Quiz 9)
