MCQs Microbiology :: Microorganisms and Disease

1.
Which of the following characteristic of the Rotavirus was important for the construction of the Rotashield vaccine?

A. The possession of a segmented RNA genome
B. A limited number of capsule types
C. The ability of monkey Rotavirus strains to cause serious illness (diarrhea) in human beings
D. The ability of the Rotavirus to be transmitted faster
Answer & Explanation
Answer: Option A
2.
Plastic implants can pose a serious nosocomial infection problem because

A. phagocytes have trouble moving on the plastic surface
B. phagocytes have trouble engulfing bacteria embedded in a biofilm
C. infected implants usually have to be surgically removed
D. all of the above
Answer & Explanation
Answer: Option D
3.
A major difference between EHEC and EPEC is

A. EHEC secretes a Shiga-like toxin and EPEC does not
B. EHEC possesses a type III secretion system and EPEC does not
C. EPEC rearranges host cell actin and EHEC does not
D. EPEC passes through the placenta to infect the fetus and EHEC does not
Answer & Explanation
Answer: Option A

4.
The nature of the poliovirus gives for oral vaccination (satin vaccine) as part of the eradication programme is

A. heat killed virus
B. live attenuated strains of all three immunological types
C. small dosage of wild-type live viruses
D. formalin-inactivated viruses
Answer & Explanation
Answer: Option B
5.
Which of the following is true regarding anthrax?

A. Anthrax is caused by a virus
B. Anthrax is highly contagious
C. Inhalation anthrax and cutaneous anthrax are caused by separate strains ofBacillus anthracis
D. Inhalation Anthrax requires infection with a large number of spores
Answer & Explanation
Answer: Option D
6.
The toxins produced by bacteria

A. kill viruses
B. encourage bacterial reproduction
C. interfere with physiological processes in the body
D. all of the above
Answer & Explanation
Answer: Option C
7.
Pseudomembraneous colitis is

A. precipitated by the use of certain antibiotics
B. caused by a gram-positive bacterium
C. caused by a spore-forming bacterium
D. all of the above
Answer & Explanation
Answer: Option D
8.
Both Mycobacterium tuberculosis and Streptococcus pneumoniae

A. are acquired by inhalation
B. have cell walls that contain a high content of mycolic acids
C. have polysaccharide capsules
D. stay in the lung and rarely, if ever, enter the bloodstream
Answer & Explanation
Answer: Option A
9.
Cholera toxin is an A-B type toxin in which the B portions bind to a receptor on a host cell and the A portion enters the cell to cause

A. ADP ribosylation of adenylate cyclase that stops production of cAMP
B. ADP ribosylation of a G protein that locks it into an active form that stimulates adenylate cyclase to make cAMP
C. cleavage of rRNA that results in disruption of ribosome function
D. ADP ribosylation of guanylate cyclase that stimulates production of cGMP
Answer & Explanation
Answer: Option B
10.
Mucus helps in protecting against pathogens by

A. lowering the pH
B. facilitating the growth of normal flora
C. blocking access and attachment of pathogens to mucosal surfaces
D. sequestering Iron
Answer & Explanation
Answer: Option C
11.
Type III secretion systems are used to inject "effector" proteins directly into a host cell.Salmonella uses a type III secretion system to help the pathogen to

A. survive the acid pH of the stomach
B. secrete LT (heat labile toxin) and ST (heat stable toxin) into the lumen of the intestine
C. survive within macrophages
D. activate T cells to proliferate and secrete cytokines
Answer & Explanation
Answer: Option C
12.
Which of these cytokines is also known under the name cachectin?

A. Interferon gamma
B. Interleukin 2
C. Tumor necrosis factor (TNF)
D. None of the above
Answer & Explanation
Answer: Option C
13.
Which is not a major defense mechanism in the stomach?

A. Proteolytic enzymes
B. Low pH
C. Dense normal flora
D. All of these
Answer & Explanation
Answer: Option C
14.
The agent responsible for causing mad cow disease is thought to be a

A. fungus B. protozoan
C. prion D. virus
Answer & Explanation
Answer: Option C
15.
The "A" subunit of diphtheria toxin

A. binds host cell receptors found on heart cells
B. cause ADP ribosylation of a factor involved in protein synthesis
C. forms cAMP that leads to fluid accumulation
D. lysis macrophages with the release of cytokines
Answer & Explanation
Answer: Option B
16.
Coxsackie virus B3, a subgroup of enteroviruses, commonly causes

A. acute hemorrhagic conjunctivitis
B. muscular dystrophy
C. myocarditis
D. gastroenteritis
Answer & Explanation
Answer: Option C
17.
Prontosil is

A. an effective antibacterial when used in animals
B. an effective antibacterial when used in in-vitro cultures
C. an effective antibacterial both in animals as well as in in-vitro cultures
D. not used as an antibacterial agent
Answer & Explanation
Answer: Option C
18.
All infections do not cause fever and all fevers are not due to infections which of the following is an example of non-infections cause of fever?

A. Typhoid
B. Chicken pox
C. Rheumatic disease
D. Malaria
Answer & Explanation
Answer: Option C
19.
Immunization with which of the following toxoid induces high titer serum antibody, but does not protect from the corresponding disease?

A. Tetanus B. Botulism
C. Diphtheria D. Shigellosis
Answer & Explanation
Answer: Option B
20.
Which of the following statements is not true regarding Mycobacterium tuberculosisand/or the disease it causes?

A. The pathogen contains mycolic acid in its cell wall
B. The pathogen can live inside macrophages
C. Antibodies to the pathogen are protective
D. None of these
Answer & Explanation
Answer: Option C
21.
What is common in catheters and ventilators?

A. They bypass important defenses of the body
B. Bacteria responsible for associated infections are usually susceptible to antibiotics
C. They predispose patients to viral rather than bacterial infections
D. They are used primarily in neonatal intensive care units
Answer & Explanation
Answer: Option A
22.
An important host defense of human beings is a dense resident microbiota associated with

A. lungs B. bladder
C. uterus D. vagina
Answer & Explanation
Answer: Option D
23.
Lactoferrin helps to protect against pathogens by

A. sequestering Iron
B. blocking sebum production
C. lowering the pH
D. facilitating the growth of normal flora
Answer & Explanation
Answer: Option A
24.
The influenza vaccine is administered each year because

A. mutations in the viral hemagglutinin may allow the virus to evade the immune response elicited by previous vaccines
B. it is a polysaccharide vaccine that does not confer long-term protection
C. the vaccine is sufficiently toxic to make it necessary to administer only a small amount at any one time
D. none of the above
Answer & Explanation
Answer: Option A
25.
Which of the following disease is caused by DNA viruses?

A. Poliomyelitis
B. Yellow fever
C. Measles
D. Small pox
Answer & Explanation
Answer: Option D
26.
Which of the following is common in the disease caused by Coryne-bacterium diphtheriaeand Bacillus anthracis?

A. Both organisms are gram-positive spore formers
B. Diphtheria toxin and edema toxin are ADP ribosylating toxins
C. The most serious disease symptoms are the direct result of toxin action
D. Both organisms cause skin and respiratory tract infections
Answer & Explanation
Answer: Option C

27.
Fatalities following influenza infection are usually due to the

A. dehydration
B. bacterial superinfection
C. damage to the heart muscle
D. formation of granulomas in the lung
Answer & Explanation
Answer: Option B

28.
Which of the following disease is not caused by microbial protein toxin?

A. Botulism
B. Diphtheria
C. Shigella dysentery
D. Tuberculosis
Answer & Explanation
Answer: Option D

29.
In the human disease cholera, what is it that actually ends up killing the victim?

A. Faulty carrier proteins
B. Dehydration and loss of nutrients
C. Too little water in the food stream
D. the toxin produced by the bacterium
Answer & Explanation
Answer: Option B

30.
Each of the 3 virulence factors of Bacillus anthracis i.e. the capsule, edema toxin and lethal toxin can affect the activity of

A. B cells
B. macrophages
C. ciliated epithelial cells
D. M cells
Answer & Explanation
Answer: Option B