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