MDS PREP
Which of the following statements about the fermentation of sugars by Anthracoid bacilli is true?
1) Anthracoid bacilli ferment glucose, maltose, lactose, and sucrose, producing acid and gas.
2). Anthracoid bacilli do not ferment glucose but ferment maltose, lactose, and sucrose.
3) Anthracoid bacilli only ferment glucose.
4) Anthracoid bacilli ferment glucose, maltose, and lactose, but not sucrose.
General Microbiology Answer: 1
Anthracoid bacilli, such as those in the genus Bacillus, are capable of fermenting various sugars, including glucose, maltose, lactose, and sucrose. This fermentation process results in the production of acid and gas, which can be detected by observing changes in the pH of the medium and the formation of gas bubbles. This statement is true as it accurately describes the typical sugar fermentation profile of these bacteria.
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.
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
Which of the following is a distinguishing feature of exotoxins?
1) Lipopolysaccharides
2) Heat stable
3) Actively secreted by cells
4) Obtained only by cell lysis
General Microbiology Answer: 3
Exotoxins are produced and secreted by bacteria into the surrounding environment. They are typically proteins that can cause damage to the host by disrupting cellular processes. This active secretion distinguishes them from endotoxins, which are part of the bacterial cell wall and are released upon cell lysis.
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 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.
Which medium is suitable for the transport of Salmonella and Shigella?
1) Cary-Blair medium
2) Thiosulfate-citrate-bile salts-sucrose (TCBS) agar
3) Hektoen enteric (HE) agar
4) Blood agar
General Microbiology Answer: 1the medium suitable for the transport of Salmonella and Shigella is Cary-Blair mediumx. This medium is designed to maintain the viability of these organisms during transport and is selective for enteric pathogens by inhibiting the growth of other non-target bacteria. TCBS agar and HE agar are used for the selective isolation and growth of these organisms, while blood agar is a general purpose medium used for various bacteria.
Which of the following statements about the fermentation of sugars by Anthracoid bacilli is true?
1) Anthracoid bacilli ferment glucose, maltose, lactose, and sucrose, producing acid and gas.
2) Anthracoid bacilli do not ferment glucose but ferment maltose, lactose, and sucrose.
3) Anthracoid bacilli only ferment glucose.
4) Anthracoid bacilli ferment glucose, maltose, and lactose, but not sucrose.
Anthracoid bacilli ferment glucose, maltose, lactose, and sucrose, producing acid and gas.