MDS PREP
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.
Which of the following compounds have the narrowest effective antimicrobial range?
1. Cresols
2. Glutaraldehydes
3. Soaps
4. 70% isopropanol
Microbiology
Answer: 3
Soaps typically have the narrowest effective antimicrobial range among the listed compounds. They are primarily effective against certain bacteria and viruses but may not be as potent against a broader spectrum of pathogens compared to glutaraldehyde or alcohols like 70% isopropanol.
Which of the following is NOT a direct method for diagnosing tuberculosis?
1) Smear examination
2) ELISA
3) Culture methods
4) Nucleic acid technology
General Microbiology Answer: 2ELISA: While ELISA (Enzyme-Linked Immunosorbent Assay) can be used to detect antibodies to the tuberculosis bacterium, it is not a direct method for diagnosing active TB infection. Direct methods include smear examination, culture, and nucleic acid technology, which detect the actual presence of the bacteria in the patient sample.
What type of vaccine is the 17D vaccine for yellow fever?
1) Live attenuated
2) Inactivated
3) Subunit
4) Toxoid
General Microbiology Answer: 1
The 17D vaccine for yellow fever is a live attenuated vaccine, meaning it contains a weakened form of the virus that can stimulate an immune response without causing the disease. This type of vaccine is effective in providing long-lasting immunity.
Which of the following statements is true about the colony morphology and cultural characteristics of Anthrax bacilli?
1) Anthrax bacilli are motile and produce a turbidity in broth.
2) The Medusa head appearance is seen in non-virulent strains of anthrax bacilli.
3) Virulent capsulated strains form smooth colonies.
4) The inverted fir tree appearance is characteristic of Anthracoid bacilli.
The Medusa head appearance is characteristic of virulent strains of anthrax bacilli, not non-virulent strains.
What is the primary reservoir for S. typhi?
1) Domestic animals
2) Insects
3) Water and food
4) Human carriers
General Microbiology Answer: 4The primary reservoir for S. typhi is Human carriers: Typhoid fever is primarily a human disease with human carriers serving as the main reservoir for the bacterium. While the bacteria can also be found in water and food, it is typically humans who carry and transmit the infection.
What is the typical pH range for optimal growth of meningococci?
1) 6.8-7.0
2) 7.4-7.6
3) 8.0-8.2
4) 7.0-7.2
The optimal pH range for the growth of meningococci is 7.4-7.6.
What type of genome do Hepatitis B viruses have?
1) ssRNA
2) dsDNA
3) ssDNA
4) dsRNA
General Microbiology Answer: 2Hepatitis B viruses possess a double-stranded DNA (dsDNA) genome, which is unique among the hepatitis viruses. This dsDNA is partially double-stranded and circular, playing a crucial role in the virus life cycle and replication.