Which type of RNA carries the genetic code for protein synthesis?
- A. mRNA
- B. tRNA
- C. rRNA
- D. snRNA
Correct Answer: A
Rationale: The correct answer is A: mRNA. mRNA carries the genetic code from the DNA in the cell nucleus to the ribosomes in the cytoplasm, where protein synthesis occurs. It serves as a template for protein synthesis by specifying the order of amino acids. tRNA (choice B) brings amino acids to the ribosome during protein synthesis. rRNA (choice C) is a structural component of ribosomes. snRNA (choice D) is involved in RNA processing and splicing, not protein synthesis. Therefore, choice A is correct as it directly carries the genetic code for protein synthesis.
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The innate immune system is always working to protect the body and does not require any special preparation to stop infection:
- A. TRUE
- B. FALSE
- C. Both answers can be correct depending on the given situation
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: TRUE. The innate immune system is the body's first line of defense against infections and is always active, providing immediate protection without prior exposure to a specific pathogen. It includes physical barriers, such as skin and mucous membranes, and cellular components like phagocytes and natural killer cells. The innate immune response is nonspecific and rapid, providing a crucial initial defense against pathogens.
Choice B is incorrect because the innate immune system is always active, even without any prior exposure to pathogens. Choice C is incorrect because the innate immune system is consistently functioning to protect the body, regardless of the situation. Choice D is incorrect as the correct answer is A.
The correct hierarchical order for virus classification is
- A. order, genus, family, subfamily, species.
- B. species, genus, family, subfamily, order.
- C. order, family, subfamily, genus, species.
- D. genus, order, family, subfamily, species.
Correct Answer: C
Rationale: The correct hierarchical order for virus classification is order, family, subfamily, genus, species. This is because classification starts at a broader level (order) and narrows down to a more specific level (species). Order comes first to group viruses based on common characteristics, followed by family, which further categorizes them. Subfamily refines the classification, then genus groups similar viruses together, and species distinguishes different strains within a genus. Choice A is incorrect because it places genus before family, which is not the correct sequence. Choice B is incorrect as it starts with species, which is the most specific level. Choice D is incorrect because it places genus at the beginning, which is too specific for the hierarchical order.
Listeria monocytogenes are:
- A. Gram-negative rod-shaped bacteria
- B. Gram-positive spherical bacteria
- C. Gram-positive rod-shaped bacteria
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C: Gram-positive rod-shaped bacteria. Listeria monocytogenes is a Gram-positive bacterium, as it retains the crystal violet stain during the Gram staining process. The bacteria are rod-shaped, not spherical. Choice A is incorrect as Listeria monocytogenes is not Gram-negative. Choice D is incorrect as Listeria monocytogenes does fall under the category of Gram-positive bacteria. The key is to remember the characteristics of Listeria monocytogenes, which are Gram-positive and rod-shaped.
Bacteriology testing is one of the methods for laboratory diagnostics of diphtheria. To grow the
- A. diphtheriae, it is necessary to know the proper conditions for causative agent cultivation. What nutrient media are optimal for Corynebacterium diphtheriae cultivation?
- B. Sugar meat pepton broth, sugar meat pepton agar
- C. Salt egg yolk agar
- D. Endomedium, Ploskirev medium
Correct Answer: B
Rationale: The correct answer is B: Sugar meat pepton broth, sugar meat pepton agar. These nutrient media are optimal for Corynebacterium diphtheriae cultivation due to their ability to support the growth of this bacterium. Sugar meat pepton broth provides a liquid medium with essential nutrients, while sugar meat pepton agar provides a solid surface for bacterial growth and isolation.
Incorrect choices:
A: Diphtheriae does not require specific conditions for cultivation.
C: Salt egg yolk agar is not commonly used for Corynebacterium diphtheriae.
D: Endomedium and Ploskirev medium are not standard media for diphtheria testing.
In order to prevent wound infection associated with surgical procedures a patient was given a synthetic antiprotozoan drug with a high activity against Helicobacter pylori. Specify this drug:
- A. Metronidazole
- B. Doxycycline hydrochloride
- C. Chingamin
- D. Acyclovir
Correct Answer: A
Rationale: The correct answer is A: Metronidazole. Metronidazole is a synthetic antiprotozoan drug with high activity against Helicobacter pylori, a bacterium that can cause wound infections. Metronidazole specifically targets anaerobic bacteria like H. pylori, making it effective in preventing wound infections.
Incorrect choices:
B: Doxycycline hydrochloride - Doxycycline is primarily used for bacterial infections, not protozoan infections like H. pylori.
C: Chingamin - Chingamin is not a commonly used drug for treating H. pylori infections or preventing wound infections.
D: Acyclovir - Acyclovir is an antiviral drug used to treat herpes infections, not bacterial or protozoan infections like H. pylori.
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