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