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