Microbiology mcq with answers PDF – Pathogenesis

Here is “Microbiology mcq with answers PDF – Pathogenesis” Chapter #7.

Question 1: What is the term for the ability of a microorganism to cause disease?

A) Virulence
B) Immunity
C) Sterility
D) Pathogenicity

Answer: A) Virulence

Question 2: Which of the following is NOT a component of the Koch’s postulates?

A) The microorganism must be isolated from a diseased individual and grown in pure culture.
B) The microorganism must cause disease when introduced into a healthy individual.
C) The microorganism must be visible under a light microscope.
D) The microorganism must be re-isolated from the experimentally infected individual.

Answer: C) The microorganism must be visible under a light microscope.

Question 3: Which term refers to the ability of a microorganism to cause severe disease in a host?

A) Infectivity
B) Virulence
C) Pathogenicity
D) Contagiousness

Answer: B) Virulence

Question 4: Which of the following is an example of an exotoxin?

A) Lipopolysaccharide (LPS)
B) Streptolysin S
C) Lipoteichoic acid
D) Peptidoglycan

Answer: B) Streptolysin S

Question 5: How do endotoxins differ from exotoxins?

A) Endotoxins are proteins released by bacteria, while exotoxins are lipopolysaccharides.
B) Endotoxins are produced by Gram-positive bacteria, while exotoxins are produced by Gram-negative bacteria.
C) Endotoxins are heat-labile, while exotoxins are heat-stable.
D) Endotoxins are structural components of the outer membrane of Gram-negative bacteria, while exotoxins are secreted proteins.

Answer: D) Endotoxins are structural components of the outer membrane of Gram-negative bacteria, while exotoxins are secreted proteins.

Question 6: Which type of pathogen can establish an infection only if the host’s immune system is compromised?

A) Obligate intracellular pathogen
B) Facultative intracellular pathogen
C) Opportunistic pathogen
D) Endotoxin-producing pathogen

Answer: C) Opportunistic pathogen

Question 7: Which of the following is an example of a direct transmission route for infectious diseases?

A) Ingesting contaminated food
B) Breathing in respiratory droplets from a cough or sneeze
C) Getting bitten by an infected mosquito
D) Touching a surface that has infectious particles and then touching the face

Answer: B) Breathing in respiratory droplets from a cough or sneeze

Question 8: What is the primary function of pili (fimbriae) in bacterial pathogenesis?

A) To facilitate bacterial movement
B) To aid in bacterial replication
C) To promote adhesion to host cells
D) To protect bacteria from antibiotics

Answer: C) To promote adhesion to host cells

Question 9: Which term describes a state of unresponsiveness to antigens from one’s own body?

A) Immunity
B) Allergy
C) Autoimmunity
D) Tolerance

Answer: D) Tolerance

Question 10: Which of the following is a mechanism that bacteria use to evade the host immune system?

A) Upregulating toll-like receptors
B) Producing antibodies against host cells
C) Antigenic variation
D) Enhancing phagocytosis

Answer: C) Antigenic variation

Question 11: Which of the following is an example of a latent infection?

A) Influenza
B) Tuberculosis
C) Common cold
D) Streptococcal throat infection

Answer: B) Tuberculosis

Question 12: How does a capsule contribute to bacterial pathogenicity?

A) It enhances bacterial movement
B) It facilitates DNA exchange between bacteria
C) It helps bacteria evade phagocytosis
D) It acts as a source of nutrients for bacteria

Answer: C) It helps bacteria evade phagocytosis

Question 13: What is a zoonotic disease?

A) A disease caused by viruses only
B) A disease that primarily affects plants
C) A disease transmitted from animals to humans
D) A disease that spreads through waterborne transmission

Answer: C) A disease transmitted from animals to humans

Question 14: Which of the following is a vector-borne transmission route for infectious diseases?

A) Inhaling respiratory droplets
B) Direct contact with the infected person’s skin
C) Consuming contaminated food
D) Being bitten by infected ticks

Answer: D) Being bitten by infected ticks

Question 15: What is the primary function of MHC molecules in the immune response?

A) To directly attack pathogens
B) To recognize pathogen-associated molecular patterns (PAMPs)
C) To present antigens to immune cells
D) To neutralize toxins produced by pathogens

Answer: C) To present antigens to immune cells

Question 16: Which of the following is a virulence factor that allows bacteria to resist phagocytosis by immune cells?

A) Antibodies
B) Complement proteins
C) Phagolysosomes
D) Capsule formation

Answer: D) Capsule formation

Question 17: What is the role of superantigens in bacterial infections?

A) They inhibit bacterial replication
B) They trigger an exaggerated immune response
C) They directly kill host cells
D) They prevent the release of endotoxins

Answer: B) They trigger an exaggerated immune response

Question 18: Which type of toxin causes the symptoms of fever, inflammation, and shock in response to Gram-negative bacterial infections?

A) Exotoxins
B) Enterotoxins
C) Lipopolysaccharides (LPS)
D) Endotoxins

Answer: D) Endotoxins

Question 19: Which of the following is an example of a chronic infection?

A) Measles
B) Chickenpox
C) Acute bacterial meningitis
D) HIV/AIDS

Answer: D) HIV/AIDS

Question 20: How do vaccines primarily protect individuals from infectious diseases?

A) By directly killing the pathogens
B) By stimulating a specific immune response against the pathogens
C) By blocking all types of pathogen entry
D) By neutralizing toxins produced by pathogens

Answer: B) By stimulating a specific immune response against the pathogens

Question 21: Which of the following best describes a reservoir in the context of infectious diseases?

A) An organism that carries a pathogen without showing symptoms of the disease
B) A place where pathogens are produced in large quantities
C) A laboratory where microbial cultures are maintained
D) A region with a high prevalence of a specific disease

Answer: A) An organism that carries a pathogen without showing symptoms of the disease

Question 22: Which of the following is an example of a protozoan pathogen?

A) Escherichia coli (E. coli)
B) Staphylococcus aureus
C) Plasmodium falciparum
D) Streptococcus pyogenes

Answer: C) Plasmodium falciparum

Question 23: What is the term for a microorganism’s genetic makeup, which can influence its ability to cause disease?

A) Virulence factors
B) Phenotype
C) Pathogenicity islands
D) Genotype

Answer: D) Genotype

Question 24: Which of the following is an example of a fomite?

A) A mosquito carrying a virus
B) A contaminated piece of fruit
C) An infected person sneezing
D) Airborne bacteria

Answer: B) A contaminated piece of fruit

Question 25: What is the primary role of the mucociliary escalator in preventing respiratory infections?

A) Producing antibodies against pathogens
B) Trapping and removing inhaled pathogens and debris
C) Destroying pathogens using enzymes
D) Stimulating fever as an immune response

Answer: B) Trapping and removing inhaled pathogens and debris

Question 26: Which type of toxin targets nerve cells and can lead to symptoms like muscle paralysis?

A) Enterotoxin
B) Cytotoxin
C) Neurotoxin
D) Hemolysin

Answer: C) Neurotoxin

Question 27: What is the mechanism of action of antiseptics?

A) Killing bacteria inside the body
B) Enhancing the immune response
C) Killing bacteria on living tissues
D) Neutralizing bacterial toxins

Answer: C) Killing bacteria on living tissues

Question 28: What role do cytokines play in the immune response to infection?

A) They are structural components of antibodies
B) They help neutralize bacterial toxins
C) They regulate immune cell communication and response
D) They are enzymes that break down bacterial cell walls

Answer: C) They regulate immune cell communication and response

Question 29: Which of the following is an example of a systemic infection?

A) Athlete’s foot
B) Urinary tract infection
C) Tuberculosis
D) Strep throat

Answer: C) Tuberculosis

Question 30: Which of the following is a common portal of entry for pathogens?

A) Healthy skin
B) Intact mucous membranes
C) Respiratory tract
D) Intact digestive system

Answer: C) Respiratory tract

Question 31: Which type of immune response involves antibodies produced by B cells?

A) Cell-mediated immunity
B) Innate immunity
C) Humoral immunity
D) Passive immunity

Answer: C) Humoral immunity

Question 32: Which of the following is an example of a viral pathogen?

A) Candida albicans
B) Escherichia coli
C) Influenza virus
D) Mycobacterium tuberculosis

Answer: C) Influenza virus

Question 33: What is the primary function of the complement system in the immune response?

A) Producing antibodies
B) Destroying infected host cells
C) Enhancing phagocytosis
D) Promoting inflammation

Answer: B) Destroying infected host cells

Question 34: What is the role of adhesins in bacterial pathogenesis?

A) To neutralize toxins
B) To prevent phagocytosis
C) To stimulate antibody production
D) To promote attachment to host cells

Answer: D) To promote attachment to host cells

Question 35: Which of the following is a characteristic of acute infections?

A) Long-lasting and persistent symptoms
B) Slow onset and gradual progression
C) Gradual decline in symptoms over time
D) Rapid onset and short duration

Answer: D) Rapid onset and short duration

Question 36: What is the term for a population in which a specific disease regularly spreads?

A) Pandemic
B) Endemic
C) Epidemic
D) Outbreak

Answer: B) Endemic

Question 37: Which of the following is an example of a Gram-negative bacterial pathogen?

A) Staphylococcus aureus
B) Streptococcus pyogenes
C) Escherichia coli
D) Clostridium botulinum

Answer: C) Escherichia coli

Question 38: What is the role of neutrophils in the immune response?

A) Producing antibodies
B) Regulating T-cell responses
C) Phagocytosing pathogens and debris
D) Recognizing antigens on infected cells

Answer: C) Phagocytosing pathogens and debris

Question 39: Which of the following is an example of a foodborne transmission route for infectious diseases?

A) Inhalation of airborne pathogens
B) Contact with contaminated surfaces
C) Transmission through sexual contact
D) Consumption of contaminated water or food

Answer: D) Consumption of contaminated water or food

Question 40: What is the primary function of memory cells in the immune response?

A) To produce antibodies
B) To initiate inflammation
C) To recognize and respond to repeat infections
D) To differentiate into various immune cell types

Answer: C) To recognize and respond to repeat infections

Question 41: Endotoxins are chemically?

A) Lipopolysaccharide
B) Polypeptide

Question 42: Exotoxins are chemically?

A) lipopolysaccharide
B) Polypeptide

Question 43: Traveler’s diarrhea (Watery, none bloody diarrhea) caused by the?

A) E.coli
B) Labile toxin
C) Both

Question 44: Bloody diarrhea associated with undercooked hamburgers caused by which kinds of toxin?

A) Verotoxin
B) Shiga Like Toxin
C) BOTH

Question 45: What is the most important cause of SEPTIC SHOCK?

A) Endotoxin
B) Exotoxin

Question 46: Which toxin produced by both gram positive and gram negative?

A) Endotoxin
B) Exotoxin

Question 47: Which toxin is produced by ONLY gram-negative bacteria?

A) Endotoxin
B) Exotoxin

Question 48: Hand washing is an important means of interrupting the chain of transmission from ONE person to ANOTHER?

A) Saph Aureus
B) Strep Agalactiae