1. : Who is known as the Father of Microbiology?
(A) Robert Koch
(B) Louis Pasteur
(C) Anton van Leeuwenhoek
(D) Joseph Lister
2. : The scientist who discovered penicillin was:
(A) Louis Pasteur
(B) Alexander Fleming
(C) Robert Koch
(D) Edward Jenner
3. : The first vaccine developed was against:
(A) Cholera
(B) Smallpox
(C) Rabies
(D) Plague
4. : Bacteria that require oxygen for growth are called:
(A) Anaerobes
(B) Facultative anaerobes
(C) Aerobes
(D) Microaerophiles
5. : The bacterial cell wall is mainly composed of:
(A) Chitin
(B) Cellulose
(C) Peptidoglycan
(D) Lipid bilayer
6. : The instrument used to sterilize culture media is:
(A) Autoclave
(B) Incubator
(C) Centrifuge
(D) Microscope
7. : Gram-positive bacteria appear __________ under microscope after Gram staining.
(A) Red
(B) Blue or violet
(C) Green
(D) Pink
8. : The process of heat-killing microorganisms in milk is called:
(A) Fermentation
(B) Pasteurization
(C) Sterilization
(D) Incubation
9. : Which structure helps bacteria in motility?
(A) Capsule
(B) Pili
(C) Flagella
(D) Ribosomes
10. : The smallest living organisms are:
(A) Viruses
(B) Protozoa
(C) Bacteria
(D) Fungi
11. : Which of the following is an example of a eukaryotic microorganism?
(A) E. coli
(B) Yeast
(C) Salmonella
(D) Mycoplasma
12. : Which staining method differentiates bacterial species into two major groups?
(A) Acid-fast stain
(B) Gram stain
(C) Simple stain
(D) Endospore stain
13. : A culture containing only one kind of microorganism is called:
(A) Mixed culture
(B) Pure culture
(C) Continuous culture
(D) Batch culture
14. : Which scientist formulated the germ theory of disease?
(A) Koch
(B) Pasteur
(C) Lister
(D) Leeuwenhoek
15. : Endospores in bacteria are formed for:
(A) Reproduction
(B) Genetic exchange
(C) Survival under harsh conditions
(D) Motility
16. : Which part of the bacterial cell controls cell division?
(A) Ribosome
(B) Nucleoid
(C) Cell wall
(D) Cytoplasm
17. : The term “pathogen” refers to:
(A) Any harmless microorganism
(B) A disease-causing microorganism
(C) A photosynthetic bacterium
(D) A decomposer
18. : Which of the following is not a prokaryote?
(A) Bacteria
(B) Archaea
(C) Fungi
(D) Cyanobacteria
19. : The structure used for bacterial conjugation is:
(A) Flagella
(B) Pili
(C) Capsule
(D) Ribosome
20. : The first person to see microorganisms under a microscope was:
(A) Koch
(B) Pasteur
(C) Leeuwenhoek
(D) Jenner
21. : The enzyme lysozyme destroys bacterial:
(A) Cytoplasm
(B) Cell wall
(C) Ribosomes
(D) Nucleoid
22. : The pH range most suitable for bacterial growth is:
(A) 1–3
(B) 4–5
(C) 6.5–7.5
(D) 8–10
23. : Which bacterial structure is responsible for adherence to surfaces?
(A) Capsule
(B) Pili
(C) Flagella
(D) Endospore
24. : Which of the following is not an aseptic technique?
(A) Sterilizing instruments
(B) Hand washing
(C) Blowing air over cultures
(D) Using disinfectants
25. : The generation time is:
(A) Time for DNA replication
(B) Time for one cell to divide into two
(C) Time for spore formation
(D) Time for cell death
26. : The bacterial chromosome is usually:
(A) Linear
(B) Circular
(C) Segmented
(D) Absent
27. : The outermost layer of Gram-negative bacteria is composed of:
(A) Lipopolysaccharide
(B) Peptidoglycan
(C) Chitin
(D) Protein coat
28. : Psychrophilic bacteria grow best at:
(A) 0–20°C
(B) 25–37°C
(C) 45–60°C
(D) 70–80°C
29. : Mesophilic bacteria prefer temperatures around:
(A) 10°C
(B) 20°C
(C) 37°C
(D) 60°C
30. : Thermophiles are microorganisms that thrive in:
(A) Cold conditions
(B) High temperature
(C) Low pH
(D) High salt
31. : Which of the following is a differential medium?
(A) Nutrient agar
(B) MacConkey agar
(C) Tryptic soy agar
(D) Peptone water
32. : The logarithmic phase in bacterial growth curve represents:
(A) Lag phase
(B) Stationary phase
(C) Exponential growth
(D) Decline phase
33. : The Gram stain was developed by:
(A) Louis Pasteur
(B) Hans Christian Gram
(C) Robert Koch
(D) Edward Jenner
34. : Bacterial spores can resist:
(A) Heat and desiccation
(B) Antibiotics only
(C) Freezing only
(D) Radiation only
35. : The bacterial capsule provides:
(A) Energy
(B) Protection against phagocytosis
(C) Protein synthesis
(D) Cell movement
36. : Viruses differ from bacteria because they:
(A) Have no cell wall
(B) Cannot reproduce outside host cells
(C) Contain both DNA and RNA
(D) Are larger than bacteria
37. : Which microscope is used to observe living cells without staining?
(A) Electron microscope
(B) Phase contrast microscope
(C) Fluorescence microscope
(D) Compound microscope
38. : The bacterial ribosome is of type:
(A) 80S
(B) 70S
(C) 60S
(D) 50S
39. : Mycoplasma is unique because it lacks:
(A) Cell wall
(B) Cell membrane
(C) Ribosomes
(D) Cytoplasm
40. : Which of these diseases is caused by a bacterium?
(A) Influenza
(B) Tuberculosis
(C) Measles
(D) Dengue
41. : The main component of bacterial flagella is:
(A) Actin
(B) Tubulin
(C) Flagellin
(D) Collagen
42. : Bacteria that can grow in the presence or absence of oxygen are:
(A) Obligate aerobes
(B) Facultative anaerobes
(C) Microaerophiles
(D) Obligate anaerobes
43. : The enzyme catalase breaks down:
(A) Hydrogen peroxide
(B) Water
(C) Carbon dioxide
(D) Glucose
44. : Which process involves transfer of genetic material by a bacteriophage?
(A) Transformation
(B) Transduction
(C) Conjugation
(D) Translation
45. : DNA replication in bacteria is:
(A) Conservative
(B) Dispersive
(C) Semiconservative
(D) Random
46. : The bacterial enzyme used in PCR is:
(A) Lipase
(B) Taq polymerase
(C) Amylase
(D) Catalase
47. : Which staining method is used for Mycobacterium tuberculosis?
(A) Gram stain
(B) Acid-fast stain
(C) Spore stain
(D) Negative stain
48. : The presence of plasmids in bacteria gives:
(A) Antibiotic resistance
(B) Motility
(C) Capsule formation
(D) Color
49. : Which bacterial shape is spiral?
(A) Coccus
(B) Bacillus
(C) Vibrio
(D) Spirillum
50. : The medium that supports the growth of all bacteria is called:
(A) Selective medium
(B) Differential medium
(C) Enriched medium
(D) Defined medium