Nokea
Identify the correct statement(s). In eukaryotic microorganisms:
- A. mRNA is short-lived (minutes).
- B. a single, circular chromosome is present.
- C. 5s, 16s, and 23s ribosomal RNA's are present.
- D. extrachromosomal DNA can be present.
Correct Answer: D
Rationale: The correct answer is D because extrachromosomal DNA, such as plasmids, can be present in eukaryotic microorganisms. This is true for certain organisms like yeast and some fungi. These DNA molecules are separate from the main chromosomal DNA and can carry additional genetic information.
A: mRNA in eukaryotic microorganisms is not short-lived; it can have varying lifespans depending on the specific mRNA molecule and cellular conditions.
B: Eukaryotic microorganisms typically have multiple linear chromosomes, not a single circular chromosome.
C: While 5s, 16s, and 23s ribosomal RNAs are present in prokaryotic organisms, eukaryotic microorganisms have different types of ribosomal RNA subunits.
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Factors important in the eradication of smallpox include
- A. Smallpox is a human pathogen; it is not found in animals.
- B. The vaccine was easily delivered and did not require sophisticated materials or technical skills
- C. The disease is contagious only when the symptoms are manifest making isolation an effective measure
- D. All of the above is correct
Correct Answer: D
Rationale: The correct answer is D because all the factors mentioned are important in the eradication of smallpox. A is correct because smallpox is specific to humans, simplifying eradication efforts. B is correct as the vaccine was easily deployable. C is correct as isolation of symptomatic individuals helped control the spread. Therefore, all choices are important in the successful eradication of smallpox.
The HIV protein that allows fusion of the viral envelope with the cell plasma membrane is
- A. gp120
- B. gp41
- C. gp160
- D. CXCR4
Correct Answer: B
Rationale: The correct answer is B: gp41. Gp41 is responsible for the fusion of the viral envelope with the cell plasma membrane by undergoing conformational changes that allow the viral and cellular membranes to merge. Gp120 attaches to the host cell receptor (CD4), facilitating the binding of the virus to the host cell. Gp160 is the precursor protein that is cleaved into gp120 and gp41 during viral maturation. CXCR4 is a cellular co-receptor used by some strains of HIV to enter host cells but is not directly involved in the fusion process.
What stimulates aldosterone secretion from the adrenal cortex?
- A. Excessive water intake
- B. Increased serum osmolality
- C. Decreased serum potassium
- D. Decreased sodium and water
Correct Answer: D
Rationale: Aldosterone secretion is stimulated by decreased sodium and water levels (renin-angiotensin-aldosterone system activation) and low blood pressure.
Which of the following statement concerning Influenza infection is NOT true?
- A. There is evidence that the infection is less common in spring/summer because the transmission of bigger droplets formed at higher temperatures requires more close contact among people
- B. People infected with Flu can spread the disease before becoming symptomatic
- C. The human strains infect cells of the respiratory tract and also extensively infect epithelial cells throughout the body, explaining the systemic symptoms of influenza
- D. The virus hemagglutinin (HA) allows cell infection via the binding to sialic acid on carbohydrates expressed on host cells
Correct Answer: C
Rationale: The correct answer is C because it states that human strains of Influenza extensively infect epithelial cells throughout the body, which is not true. Influenza primarily infects cells of the respiratory tract, leading to respiratory symptoms. Systemic symptoms such as fever, fatigue, and muscle aches are more related to the body's immune response rather than widespread infection of epithelial cells throughout the body. This statement is incorrect as it misrepresents the pathogenesis of Influenza. Choices A, B, and D are incorrect because they are all true statements supported by scientific evidence regarding Influenza transmission, asymptomatic spread, and viral entry mechanism, respectively.
A client is being taught about the transmission of HIV and is taught that body fluids such as blood,semen and vaginal secretions can transmit the virus. What is the other body fluid that the HIV virus can be transmitted through?
- A. Saliva
- B. Tears
- C. Sweat
- D. Breast milk
Correct Answer: D
Rationale: HIV can be transmitted through breast milk,making it a risk factor for mother-to-child transmission.