Nokea
Production of RNA from DNA is called
- A. Transposition
- B. Translation
- C. Transcription
- D. RNA splicing
Correct Answer: C
Rationale: The correct answer is C: Transcription. Transcription is the process of synthesizing RNA from a DNA template. During transcription, RNA polymerase binds to the DNA and produces a complementary RNA strand. This process is essential for gene expression.
Explanation for why other choices are incorrect:
A: Transposition involves the movement of genetic elements within a genome, not the production of RNA from DNA.
B: Translation is the process of synthesizing proteins from mRNA, not the production of RNA from DNA.
D: RNA splicing is the process of removing introns and joining exons in pre-mRNA to produce mature mRNA, not the initial production of RNA from DNA.
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All of the statements about Rotaviruses are correct EXCEPT
- A. non-specific antiviral therapy is available
- B. Rotaviruses are ubiquitous worldwide
- C. Rotaviruses are a major cause of meningitis
- D. large amounts of viruses are released in fecal matter
Correct Answer: C
Rationale: The correct answer is C because Rotaviruses are not a major cause of meningitis; they primarily cause gastroenteritis. This is because Rotaviruses infect the gastrointestinal tract, not the central nervous system. Choice A is incorrect because there is no specific antiviral therapy for Rotaviruses. Choice B is correct as Rotaviruses are indeed widespread globally. Choice D is correct as Rotaviruses are shed in large amounts in feces, contributing to their ability to spread easily.
Which of the following diseases is transmitted by the fecal–oral route?
- A. Ehrlichiosis
- B. Peptic ulcer
- C. Lyme disease
- D. Tularemia
Correct Answer: B
Rationale: The correct answer is B: Peptic ulcer. Peptic ulcers are commonly caused by Helicobacter pylori bacteria, which can be transmitted through the fecal-oral route. This means that the bacteria from infected feces can be ingested through contaminated food or water, leading to the development of peptic ulcers in the gastrointestinal tract.
Incorrect choices:
A: Ehrlichiosis - Ehrlichiosis is a tick-borne disease transmitted through the bite of an infected tick, not through the fecal-oral route.
C: Lyme disease - Lyme disease is also transmitted through the bite of an infected tick, specifically the black-legged tick.
D: Tularemia - Tularemia is a bacterial disease typically transmitted through insect bites, handling of infected animals, or ingestion of contaminated water, not through the fecal-oral route.
Which of the following is a primary function of bacterial capsules?
- A. Energy production
- B. Protection from desiccation
- C. Adhesion and immune evasion
- D. DNA replication
Correct Answer: C
Rationale: The correct answer is C: Adhesion and immune evasion. Bacterial capsules serve as a protective layer that aids in adhesion to surfaces and host cells, allowing bacteria to colonize and evade the immune system. This function is crucial for bacterial survival and pathogenicity. Choices A and D are incorrect because energy production and DNA replication are not primary functions of bacterial capsules. Choice B is incorrect because while bacterial capsules do provide some protection from desiccation, their primary function lies in adhesion and immune evasion.
Etiological factors for the infectious diseases are often microorganisms with various ultrastructure. Which of the following microorganism groups relates to the eukaryotes?
- A. Protozoa
- B. Viruses
- C. Viroids
- D. Prions
Correct Answer: A
Rationale: The correct answer is A: Protozoa. Protozoa are eukaryotic microorganisms, meaning they have a true nucleus and membrane-bound organelles. This relates to the question as eukaryotes are organisms with complex cells containing these features. Viruses (B) are non-living entities that require a host cell to replicate, lacking cellular structures. Viroids (C) are smaller than viruses and consist of only RNA, lacking a protein coat. Prions (D) are misfolded proteins causing diseases but are not considered microorganisms nor do they have cellular structure. Thus, protozoa are the only eukaryotic microorganism group among the options.
Which bacterial structure allows for attachment to host cells?
- A. Flagella
- B. Fimbriae
- C. Capsule
- D. Endospore
Correct Answer: B
Rationale: The correct answer is B: Fimbriae. Fimbriae are hair-like appendages found on the surface of bacteria that enable attachment to host cells. This attachment is crucial for establishing infection. Flagella (A) are used for movement, not attachment. Capsules (C) provide protection and help evade the host immune system, but do not directly facilitate attachment. Endospores (D) are dormant structures for survival, not for attachment to host cells. Fimbriae specifically aid in adherence to host cells, making them the correct choice in this context.