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