MDS PREP
What is the typical color of Salmonella colonies on MacConkey agar, except for Sh. Sonnei?
1) Colorless
2) Pink
3) Red
4) Yellow
General Microbiology Answer: 1Salmonella species, excluding Shigella sonnei, which is lactose non-fermenting, will ferment lactose in MacConkey agar, turning the colonies pink due to the formation of acidic end-products
The period from disease initiation to disease detection in non-infectious disease is called -
1. Incubation period
2. Serial interval
3. Latent period
4. Lag time
Microbiology
Answer: 3
Incubation period: This term is typically used for
infectious diseases and refers to the time between exposure to the
infectious agent and the onset of symptoms.
Serial interval: This refers to the time between
successive cases in a chain of transmission, specifically in infectious
diseases.
Latent period: This is the time from the initiation of
the disease process (or exposure to a risk factor) until the disease is
detectable or until symptoms appear. In non-infectious diseases, this period
can be significant, as the disease may be developing without any noticeable
symptoms.
Lag time: This term can refer to various delays in
processes but is not specifically defined in the context of disease
initiation and detection.
Most bacterial endotoxins are composed of
1. pure carbohydrates
2. mucoprotein complexes
3. pure lipids
4. lipoprotein-polysaccharide complexes
Microbiology
Answer: 4
Most bacterial endotoxins are composed of lipoprotein-polysaccharide complexes
What is the characteristic odor of cultures of proteus bacilli?
1) Fruity
2) Fishy or seminal
3) Sweet
4) Foul
General Microbiology Answer: 2Proteus bacilli are known for their characteristic swarming motility on agar and a distinctive odor, which is often described as fishy or seminal. This is due to the production of ammonia and indole as metabolic byproducts.
What disease is associated with inhalation of dust from infected wool?
1) Cutaneous anthrax
2) Pulmonary anthrax
3) Gastrointestinal anthrax
4) None of the above
Pulmonary anthrax is associated with inhalation of dust from infected wool.
Which of the following is NOT a method used to produce a recombinant hepatitis B vaccine?
1) Cloning the HBsAg gene in E. coli
2) Cloning the HBsAg gene in yeasts Saccharomyces cerevisae
3) Extracting and purifying HBsAg particles from infected human plasma
4) Using baculovirus vectors to produce HBsAg in insect cells
General Microbiology Answer: 1
While recombinant hepatitis B vaccines are produced using various methods, cloning the HBsAg gene in E. coli is not one of them. Instead, the gene is typically cloned in yeast or insect cells to produce the surface antigen for the vaccine.
What is the primary mechanism of action of the PCR test in diagnosing HIV infection?
1) Amplification of viral RNA or DNA
2) Detection of specific antibodies to HIV
3) Detection of the HIV virus directly
4) Measurement of the immune response to the virus
General Microbiology Answer: 1
The primary mechanism of action of the PCR test in diagnosing HIV infection is the amplification of viral RNA or DNA, allowing for the detection of the virus.
Two important factors for initiation of caries by oral streptococci are
1 production of glucosyl transferase and synthesis of insoluble dextran
2. production of acid and production or protease
3. production of collagenase and pro- duct ion of hyaluronidase
4. fermentation of mannitol and sorbitol and production of protease.
Microbiology
Answer: 1
Two important factors for initiation of caries by oral streptococci are production of glucosyl transferase and synthesis of insoluble dextran