Microbiology MCQs (Quiz 7) Posted on June 8, 2026June 10, 2026Author agropublishers 0 1. Agar begins to solidify at temperature ~ ______________°C after cooling from its molten state 90-100 40-45 65-70 15-20 2. Which microscope is most suitable for the routine identification of bacterial cell shape and arrangement in stained preparations? Transmission electron microscope Bright-field microscope Scanning electron microscope Dark-field microscope 3. What is the main sterilizing agent in an autoclave? Dry heat Chemical disinfectants Ultraviolet light High-pressure steam 4. A bacterium moves away from a disinfectant solution. This is an example of ___________________ Positive chemotaxis Negative chemotaxis Phototaxis Aerotaxis 5. Joseph Lister applied which scientific principle to reduce surgical infections? Cell Theory Koch’s Postulates Theory of Evolution Pasteur’s Germ Theory 6. Why is air removal essential before sterilization begins in an autoclave? Air causes media solidification Air increases microbial growth Air reduces steam penetration and effective temperature Air damages equipment 7. The medium containing agar and nutrients is called ___________ Solid medium Selective medium Liquid medium Broth medium 8. A microorganism that uses glucose as both an energy source and a carbon source is classified as a _____________ Photoautotroph Chemoheterotroph Chemoautotroph Phototroph 9. ________________ is the primary source of agar used in microbiological media Fungi Marine algae Bacteria Protozoa 10. A microbiologist wants to obtain isolated colonies from a mixed bacterial culture. Which medium would be most appropriate? Buffer solution Sterile water Nutrient broth Nutrient agar plate Loading … Question 1 of 10 Microbiology MCQs (Quiz 7)
