Nokea
Which of the following bacteria is capable of surviving in extreme heat?
- A. Escherichia coli
- B. Bacillus subtilis
- C. Staphylococcus aureus
- D. Clostridium botulinum
Correct Answer: B
Rationale: The correct answer is B: Bacillus subtilis. Bacillus subtilis is a thermophilic bacterium capable of surviving in extreme heat due to its heat-resistant spores. It forms spores when exposed to unfavorable conditions, allowing it to withstand high temperatures. Escherichia coli (A), Staphylococcus aureus (C), and Clostridium botulinum (D) are mesophilic bacteria that do not have the same heat resistance mechanisms as Bacillus subtilis, making them unable to survive in extreme heat conditions.
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Extrachromosomal carriers of the genetic information in bacteria are:
- A. Mesosomes
- B. Plasmids
- C. Ribosomes
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B: Plasmids. Plasmids are extrachromosomal DNA molecules found in bacteria that can replicate independently of the bacterial chromosome. They carry additional genetic information, such as antibiotic resistance genes or virulence factors. Mesosomes (choice A) are not involved in carrying genetic information; they are infoldings of the cell membrane. Ribosomes (choice C) are cellular organelles responsible for protein synthesis, not carriers of genetic information. Choice D is incorrect as plasmids are indeed extrachromosomal carriers of genetic information in bacteria.
A dentist has detected symptoms of parodontosis in a patient. What antiprotozoal drug should be prescribed?
- A. Metronidazole
- B. Levamisole
- C. Griseofulvin
- D. Mykoseptin
Correct Answer: A
Rationale: The correct answer is A: Metronidazole. Parodontosis is a condition caused by bacterial infection, not protozoal infection. Metronidazole is an effective antibiotic commonly used to treat bacterial infections in the oral cavity, including those associated with parodontosis. Levamisole is an anthelmintic drug used to treat parasitic worm infections, not suitable for parodontosis. Griseofulvin is an antifungal medication used for fungal infections, not indicated for parodontosis. Mykoseptin is not a recognized drug and is likely a distractor. Therefore, based on the bacterial nature of parodontosis, Metronidazole is the appropriate choice.
(+) ssRNA viruses that have been isolated from birds, cats, dogs, pigs, sheep, cows, and humans and are a major cause of gastroenteritis are the:
- A. rotaviruses
- B. caliciviruses
- C. adenoviruses
- D. noroviruses
Correct Answer: B
Rationale: The correct answer is B: caliciviruses. Caliciviruses are known to be (+) ssRNA viruses that cause gastroenteritis in a wide range of animals, including birds, cats, dogs, pigs, sheep, cows, and humans. These viruses are highly contagious and can spread through contaminated food or water. Rotaviruses (A) are also a common cause of gastroenteritis, but they are not exclusively isolated from the mentioned animals. Adenoviruses (C) typically cause respiratory or eye infections, not gastroenteritis. Noroviruses (D) are also a major cause of gastroenteritis in humans, but they are not commonly found in animals other than humans.
A unique number that aids in finding additional toxicological information about a specific substance is the
- A. CAS number.
- B. atomic number.
- C. DOT ID number.
- D. RTECS number.
Correct Answer: D
Rationale: The correct answer is D: RTECS number. The Registry of Toxic Effects of Chemical Substances (RTECS) number is a unique identifier assigned to chemicals and substances known to cause toxicological effects. It aids in accessing detailed toxicological information such as acute toxicity, carcinogenicity, and mutagenicity. The CAS number (A) is a unique numerical identifier for chemical compounds, not specifically for toxicological information. The atomic number (B) is the number of protons in an element's nucleus, unrelated to toxicology. The DOT ID number (C) is used for hazardous materials transportation, not for toxicological information. Therefore, the RTECS number is the correct choice for finding toxicological information about a specific substance.
A smear prepared from material obtained from patient with suspected diphtheria contains yellow bacilli with blue grains at their ends. What staining was used in this case?
- A. Ziehl-Nielsen
- B. Kozlovsky
- C. Romanovsky
- D. Loefler
Correct Answer: D
Rationale: The correct answer is D: Loefler. This staining method is used for identifying Corynebacterium diphtheriae, the causative agent of diphtheria. It involves using methylene blue and basic fuchsin to stain the bacteria. The yellow bacilli with blue grains at their ends indicate the characteristic appearance of C. diphtheriae when stained using the Loefler method.
Choice A: Ziehl-Nielsen is used for acid-fast bacteria like Mycobacterium tuberculosis.
Choice B: Kozlovsky is not a standard staining method in microbiology.
Choice C: Romanovsky is used for blood smears to identify malaria parasites.