BIO 250 MICROBIOLOGY VERIFIED ANSWERS AND QUESTIONS -
MOST RECENT EDITION (2026/2027)
1. What is the study of microorganisms called?
• A) Biology
• B) Microbiology
• C) Pathology
• D) Immunology ANSWER : B) Microbiology
2. Who is considered the "Father of Microbiology"?
• A) Louis Pasteur
• B) Robert Koch
• C) Anton van Leeuwenhoek
• D) Edward Jenner ANSWER : C) Anton van Leeuwenhoek
3. Which scientist disproved spontaneous generation?
• A) Anton van Leeuwenhoek
• B) Louis Pasteur
• C) Alexander Fleming
• D) Joseph Lister ANSWER : B) Louis Pasteur
4. What are Koch's postulates used for?
• A) Identifying vitamins
• B) Establishing disease causation
• C) Classifying bacteria
• D) Measuring growth rates ANSWER : B) Establishing disease
causation
5. Which of the following is NOT a type of microorganism?
• A) Bacteria
, • B) Viruses
• C) Protozoa
• D) Mammals ANSWER : D) Mammals
6. What type of microscope uses visible light?
• A) Electron microscope
• B) Light microscope
• C) Scanning probe microscope
• D) Atomic force microscope ANSWER : B) Light microscope
7. The resolution of a microscope refers to:
• A) Magnification power
• B) Ability to distinguish two points as separate
• C) Field of view size
• D) Light intensity ANSWER : B) Ability to distinguish two points as
separate
8. What is the maximum magnification of a typical light microscope?
• A) 100x
• B) 500x
• C) 1000x
• D) 10,000x ANSWER : C) 1000x
9. Which staining technique differentiates bacteria into two groups?
• A) Simple stain
• B) Negative stain
• C) Gram stain
• D) Acid-fast stain ANSWER : C) Gram stain
10. What color do Gram-positive bacteria appear after Gram staining?
• A) Red/Pink
• B) Purple/Blue
• C) Green
, • D) Yellow ANSWER : B) Purple/Blue
11. Microorganisms that cause disease are called:
• A) Commensals
• B) Pathogens
• C) Symbionts
• D) Mutualists ANSWER : B) Pathogens
12. The germ theory of disease was developed by:
• A) Louis Pasteur and Robert Koch
• B) Anton van Leeuwenhoek
• C) Edward Jenner
• D) Ignaz Semmelweis ANSWER : A) Louis Pasteur and Robert Koch
13. Which scientist developed the first vaccine?
• A) Louis Pasteur
• B) Robert Koch
• C) Edward Jenner
• D) Jonas Salk ANSWER : C) Edward Jenner
14. Aseptic technique is used to:
• A) Kill all microorganisms
• B) Prevent contamination
• C) Enhance growth
• D) Identify species ANSWER : B) Prevent contamination
15. Which of the following is a eukaryotic microorganism?
• A) Bacteria
• B) Archaea
• C) Fungi
• D) Viruses ANSWER : C) Fungi
16. The basic unit of life is the:
, • A) Atom
• B) Molecule
• C) Cell
• D) Tissue ANSWER : C) Cell
17. Microorganisms are important in:
• A) Nutrient cycling
• B) Food production
• C) Biotechnology
• D) All of the above ANSWER : D) All of the above
18. Which microscope provides the highest magnification?
• A) Light microscope
• B) Compound microscope
• C) Electron microscope
• D) Phase-contrast microscope ANSWER : C) Electron microscope
19. The first antibiotics were discovered by:
• A) Louis Pasteur
• B) Alexander Fleming
• C) Robert Koch
• D) Joseph Lister ANSWER : B) Alexander Fleming
20. What is the approximate size range of most bacteria?
• A) 0.1-0.5 μm
• B) 0.5-5 μm
• C) 5-50 μm
• D) 50-500 μm ANSWER : B) 0.5-5 μm
21. Oil immersion is used to:
• A) Increase resolution
• B) Preserve specimens
MOST RECENT EDITION (2026/2027)
1. What is the study of microorganisms called?
• A) Biology
• B) Microbiology
• C) Pathology
• D) Immunology ANSWER : B) Microbiology
2. Who is considered the "Father of Microbiology"?
• A) Louis Pasteur
• B) Robert Koch
• C) Anton van Leeuwenhoek
• D) Edward Jenner ANSWER : C) Anton van Leeuwenhoek
3. Which scientist disproved spontaneous generation?
• A) Anton van Leeuwenhoek
• B) Louis Pasteur
• C) Alexander Fleming
• D) Joseph Lister ANSWER : B) Louis Pasteur
4. What are Koch's postulates used for?
• A) Identifying vitamins
• B) Establishing disease causation
• C) Classifying bacteria
• D) Measuring growth rates ANSWER : B) Establishing disease
causation
5. Which of the following is NOT a type of microorganism?
• A) Bacteria
, • B) Viruses
• C) Protozoa
• D) Mammals ANSWER : D) Mammals
6. What type of microscope uses visible light?
• A) Electron microscope
• B) Light microscope
• C) Scanning probe microscope
• D) Atomic force microscope ANSWER : B) Light microscope
7. The resolution of a microscope refers to:
• A) Magnification power
• B) Ability to distinguish two points as separate
• C) Field of view size
• D) Light intensity ANSWER : B) Ability to distinguish two points as
separate
8. What is the maximum magnification of a typical light microscope?
• A) 100x
• B) 500x
• C) 1000x
• D) 10,000x ANSWER : C) 1000x
9. Which staining technique differentiates bacteria into two groups?
• A) Simple stain
• B) Negative stain
• C) Gram stain
• D) Acid-fast stain ANSWER : C) Gram stain
10. What color do Gram-positive bacteria appear after Gram staining?
• A) Red/Pink
• B) Purple/Blue
• C) Green
, • D) Yellow ANSWER : B) Purple/Blue
11. Microorganisms that cause disease are called:
• A) Commensals
• B) Pathogens
• C) Symbionts
• D) Mutualists ANSWER : B) Pathogens
12. The germ theory of disease was developed by:
• A) Louis Pasteur and Robert Koch
• B) Anton van Leeuwenhoek
• C) Edward Jenner
• D) Ignaz Semmelweis ANSWER : A) Louis Pasteur and Robert Koch
13. Which scientist developed the first vaccine?
• A) Louis Pasteur
• B) Robert Koch
• C) Edward Jenner
• D) Jonas Salk ANSWER : C) Edward Jenner
14. Aseptic technique is used to:
• A) Kill all microorganisms
• B) Prevent contamination
• C) Enhance growth
• D) Identify species ANSWER : B) Prevent contamination
15. Which of the following is a eukaryotic microorganism?
• A) Bacteria
• B) Archaea
• C) Fungi
• D) Viruses ANSWER : C) Fungi
16. The basic unit of life is the:
, • A) Atom
• B) Molecule
• C) Cell
• D) Tissue ANSWER : C) Cell
17. Microorganisms are important in:
• A) Nutrient cycling
• B) Food production
• C) Biotechnology
• D) All of the above ANSWER : D) All of the above
18. Which microscope provides the highest magnification?
• A) Light microscope
• B) Compound microscope
• C) Electron microscope
• D) Phase-contrast microscope ANSWER : C) Electron microscope
19. The first antibiotics were discovered by:
• A) Louis Pasteur
• B) Alexander Fleming
• C) Robert Koch
• D) Joseph Lister ANSWER : B) Alexander Fleming
20. What is the approximate size range of most bacteria?
• A) 0.1-0.5 μm
• B) 0.5-5 μm
• C) 5-50 μm
• D) 50-500 μm ANSWER : B) 0.5-5 μm
21. Oil immersion is used to:
• A) Increase resolution
• B) Preserve specimens
