Microbiology MCQs

  • Which of the following is a prokaryotic cell?
    • A) Plant cell
    • B) Animal cell
    • C) Bacterial cell
    • D) Fungal cell
    • Answer: C) Bacterial cell
  • Which bacterial structure is responsible for attachment to surfaces?
    • A) Capsule
    • B) Flagella
    • C) Pili
    • D) Ribosomes
    • Answer: C) Pili
  • The Gram staining technique differentiates bacteria based on their:
    • A) Shape
    • B) Size
    • C) Cell wall composition
    • D) Metabolic activity
    • Answer: C) Cell wall composition
  • Which of the following is an example of a pathogenic fungus?
    • A) Saccharomyces cerevisiae
    • B) Aspergillus niger
    • C) Candida albicans
    • D) Penicillium notatum
    • Answer: C) Candida albicans
  • Which of the following is not a characteristic of viruses?
    • A) They are obligate intracellular parasites
    • B) They contain ribosomes
    • C) They have either DNA or RNA
    • D) They lack cellular structure
    • Answer: B) They contain ribosomes
  • In the bacterium Escherichia coli, the plasmids are:
    • A) Essential for survival
    • B) Part of the chromosomal DNA
    • C) Circular DNA molecules
    • D) Organelles
    • Answer: C) Circular DNA molecules
  • Which of the following is a common method for sterilizing heat-sensitive materials?
    • A) Autoclaving
    • B) Boiling
    • C) Filtration
    • D) Incineration
    • Answer: C) Filtration
  • The process of converting nitrogen gas to ammonia is called:
    • A) Nitrogen fixation
    • B) Nitrification
    • C) Denitrification
    • D) Ammonification
    • Answer: A) Nitrogen fixation
  • Which antibiotic targets bacterial cell wall synthesis?
    • A) Tetracycline
    • B) Penicillin
    • C) Streptomycin
    • D) Erythromycin
    • Answer: B) Penicillin
  • Which type of microorganism is responsible for causing malaria?
    • A) Bacterium
    • B) Virus
    • C) Protozoan
    • D) Fungus
    • Answer: C) Protozoan
  • Which of the following is a characteristic of all viruses?
    • A) Presence of ribosomes
    • B) Cellular structure
    • C) Protein coat (capsid)
    • D) Ability to reproduce independently
    • Answer: C) Protein coat (capsid)
  • Which medium is used to culture bacteria in the laboratory?
    • A) Agar
    • B) Gelatin
    • C) Nutrient broth
    • D) Both A and C
    • Answer: D) Both A and C
  • Which technique is used to separate DNA fragments based on size?
    • A) PCR
    • B) Gel electrophoresis
    • C) Western blotting
    • D) ELISA
    • Answer: B) Gel electrophoresis
  • Which type of immunity involves antibodies circulating in blood?
    • A) Cell-mediated immunity
    • B) Humoral immunity
    • C) Innate immunity
    • D) Adaptive immunity
    • Answer: B) Humoral immunity
  • The term ‘aseptic technique’ refers to:
    • A) Techniques for killing bacteria
    • B) Techniques to avoid contamination
    • C) Techniques for growing bacteria
    • D) Techniques for identifying bacteria
    • Answer: B) Techniques to avoid contamination
  • Which bacterium is known for causing tuberculosis?
    • A) Mycobacterium tuberculosis
    • B) Escherichia coli
    • C) Staphylococcus aureus
    • D) Bacillus anthracis
    • Answer: A) Mycobacterium tuberculosis
  • Which of the following is a method of genetic recombination in bacteria?
    • A) Transformation
    • B) Mutation
    • C) Binary fission
    • D) Conjugation
    • Answer: A) Transformation
  • Which microorganism is commonly used in the production of bread and beer?
    • A) Bacteria
    • B) Protozoa
    • C) Yeast
    • D) Viruses
    • Answer: C) Yeast
  • Which component of the bacterial cell wall is primarily responsible for its rigidity?
    • A) Lipids
    • B) Polysaccharides
    • C) Peptidoglycan
    • D) Nucleic acids
    • Answer: C) Peptidoglycan
  • Which process describes the exchange of genetic material between two bacterial cells through direct contact?
    • A) Transformation
    • B) Transduction
    • C) Conjugation
    • D) Binary fission
    • Answer: C) Conjugation
  • Which of the following is used to identify bacterial species based on their ability to ferment different sugars?
    • A) Gram staining
    • B) Biochemical tests
    • C) PCR
    • D) Electron microscopy
    • Answer: B) Biochemical tests
  • Which type of microorganism can be classified as a cyanobacterium?
    • A) Blue-green algae
    • B) Protozoan
    • C) Fungi
    • D) Virus
    • Answer: A) Blue-green algae
  • What is the primary role of ribosomes in cells?
    • A) DNA replication
    • B) Protein synthesis
    • C) Energy production
    • D) Cell division
    • Answer: B) Protein synthesis
  • Which type of bacteria are characterized by a thick peptidoglycan layer in their cell walls?
    • A) Gram-positive bacteria
    • B) Gram-negative bacteria
    • C) Acid-fast bacteria
    • D) Mycoplasmas
    • Answer: A) Gram-positive bacteria
  • Which disease is caused by the bacterium Vibrio cholerae?
    • A) Tuberculosis
    • B) Cholera
    • C) Syphilis
    • D) Leprosy
    • Answer: B) Cholera
  • The primary function of bacterial capsules is:
    • A) To aid in motility
    • B) To protect against phagocytosis
    • C) To help in DNA replication
    • D) To facilitate cell division
    • Answer: B) To protect against phagocytosis
  • Which of the following viruses is known for causing the common cold?
    • A) Influenza virus
    • B) Rhinovirus
    • C) Hepatitis B virus
    • D) Human immunodeficiency virus (HIV)
    • Answer: B) Rhinovirus
  • Which process involves the transfer of genetic material from one bacterial cell to another via a bacteriophage?
    • A) Conjugation
    • B) Transduction
    • C) Transformation
    • D) Binary fission
    • Answer: B) Transduction
  • Which bacterial structure is primarily involved in movement?
    • A) Pili
    • B) Capsule
    • C) Flagella
    • D) Endospore
    • Answer: C) Flagella
  • Which type of microorganism is used in the production of antibiotics like penicillin?
    • A) Bacteria
    • B) Yeast
    • C) Protozoa
    • D) Fungi
    • Answer: D) Fungi
  • Which of the following is an obligate intracellular parasite?
    • A) Bacteria
    • B) Protozoa
    • C) Virus
    • D) Fungi
    • Answer: C) Virus
  • Which of the following is a method used to test for antibiotic susceptibility in bacteria?
    • A) ELISA
    • B) Gram staining
    • C) Disk diffusion method
    • D) PCR
    • Answer: C) Disk diffusion method
  • Which term describes the ability of bacteria to take up free DNA from the environment?
    • A) Conjugation
    • B) Transduction
    • C) Transformation
    • D) Binary fission
    • Answer: C) Transformation
  • Which bacterium is commonly associated with food poisoning from undercooked poultry?
    • A) Salmonella enterica
    • B) Staphylococcus aureus
    • C) Escherichia coli
    • D) Bacillus cereus
    • Answer: A) Salmonella enterica
  • Which of the following is a non-pathogenic bacterium used in probiotic supplements?
    • A) Escherichia coli
    • B) Lactobacillus acidophilus
    • C) Mycobacterium tuberculosis
    • D) Vibrio cholerae
    • Answer: B) Lactobacillus acidophilus
  • Which type of microscope is best suited for observing the detailed internal structures of a cell?
    • A) Light microscope
    • B) Scanning electron microscope
    • C) Transmission electron microscope
    • D) Fluorescence microscope
    • Answer: C) Transmission electron microscope
  • Which disease is associated with the bacterium Clostridium tetani?
    • A) Tetanus
    • B) Tuberculosis
    • C) Botulism
    • D) Anthrax
    • Answer: A) Tetanus
  • Which microorganism is used in the fermentation process to produce yogurt?
    • A) Candida albicans
    • B) Streptococcus thermophilus
    • C) Escherichia coli
    • D) Staphylococcus aureus
    • Answer: B) Streptococcus thermophilus
  • Which type of virus has an RNA genome and is known to cause acquired immunodeficiency syndrome (AIDS)?
    • A) DNA virus
    • B) Retrovirus
    • C) Herpesvirus
    • D) Hepadnavirus
    • Answer: B) Retrovirus
  • The use of antibiotics to control bacterial growth on surfaces is known as:
    • A) Sterilization
    • B) Disinfection
    • C) Antisepsis
    • D) Sanitization
    • Answer: B) Disinfection
  • Which of the following bacterial structures is involved in the formation of endospores?
    • A) Capsule
    • B) Cell wall
    • C) Cytoplasm
    • D) Spore coat
    • Answer: D) Spore coat
  • Which bacterial genus is known for its ability to form endospores and is used in the production of antibiotics?
    • A) Bacillus
    • B) Clostridium
    • C) Staphylococcus
    • D) Mycobacterium
    • Answer: A) Bacillus
  • Which type of medium is selective for Gram-negative bacteria?
    • A) Mannitol salt agar
    • B) MacConkey agar
    • C) Blood agar
    • D) Nutrient agar
    • Answer: B) MacConkey agar
  • Which microorganism is known for its role in nitrogen fixation in the soil?
    • A) Rhizobium
    • B) Bacillus
    • C) Aspergillus
    • D) Saccharomyces
    • Answer: A) Rhizobium
  • Which process is used to kill all microorganisms, including spores, on surfaces?
    • A) Disinfection
    • B) Sterilization
    • C) Sanitization
    • D) Antisepsis
    • Answer: B) Sterilization
  • Which of the following bacteria is a common cause of urinary tract infections (UTIs)?
    • A) Staphylococcus epidermidis
    • B) Escherichia coli
    • C) Clostridium difficile
    • D) Pseudomonas aeruginosa
    • Answer: B) Escherichia coli
  • The primary function of bacterial pili is to:
    • A) Aid in DNA replication
    • B) Facilitate motility
    • C) Enable adhesion to surfaces
    • D) Produce toxins
    • Answer: C) Enable adhesion to surfaces
  • Which of the following is a characteristic feature of viruses but not of bacteria?
    • A) Presence of a cell wall
    • B) Presence of ribosomes
    • C) Presence of a nucleic acid genome
    • D) Obligate intracellular parasitism
    • Answer: D) Obligate intracellular parasitism
  • Which bacteria are known to cause infections in wounds and are often resistant to multiple antibiotics?
    • A) Streptococcus pyogenes
    • B) Staphylococcus aureus
    • C) Bacillus anthracis
    • D) Neisseria gonorrhoeae
    • Answer: B) Staphylococcus aureus
  • Which term describes the process by which bacteria convert nitrate to nitrogen gas?
    • A) Nitrogen fixation
    • B) Nitrification
    • C) Denitrification
    • D) Ammonification
    • Answer: C) Denitrification