Nursing Elites

1. What is the role of RNA interference in silencing genes?

• A. Increases protein production
• B. Promotes gene mutation
• C. Inhibits the expression of specific genes
• D. Repairs damaged DNA

Correct answer: C

Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, 'Inhibits the expression of specific genes,' is the correct role of RNA interference in silencing genes. Options A, B, and D are incorrect because RNA interference does not increase protein production, promote gene mutation, or repair damaged DNA; its primary function is to inhibit gene expression by degrading or interfering with mRNA.

2. Which of the following is an example of stabilizing selection?

• A. Selection that favors extreme traits in a population
• B. Selection that removes individuals with extreme traits
• C. Selection that maintains the current average trait in a population
• D. Selection that favors one specific trait over all others

Correct answer: C

Rationale: - Stabilizing selection is a type of natural selection that favors the intermediate variants in a population, while selecting against the extreme traits. This results in the maintenance of the current average trait in the population. - Option A is incorrect because stabilizing selection does not favor extreme traits; instead, it favors the average trait. - Option B is incorrect because stabilizing selection does not remove individuals with extreme traits; it acts against extreme traits by favoring the intermediate variants. - Option D is incorrect because stabilizing selection does not favor one specific trait over all others; it favors the average trait by selecting against extreme traits.

3. Which of the following is NOT a function of the liver?

• A. nutrient processing
• B. blood filtration and detoxification
• C. cholesterol and lipoprotein production
• D. insulin production and blood sugar regulation

Correct answer: D

Rationale: The correct answer is D. The liver does not produce insulin; instead, insulin is produced by the pancreas. The liver plays a crucial role in regulating blood sugar levels by storing and releasing glucose but does not directly produce insulin. Choices A, B, and C are functions of the liver. Nutrient processing, blood filtration, detoxification, cholesterol, and lipoprotein production are essential roles performed by the liver to maintain overall metabolic balance and health.

4. Which part of the nervous system is responsible for the “fight-or-flight” response?

• A. Somatic nervous system
• B. Parasympathetic nervous system
• C. Sympathetic nervous system
• D. Enteric nervous system

Correct answer: C

Rationale: The sympathetic nervous system is responsible for the 'fight-or-flight' response, triggering the body's automatic response to a perceived threat or danger. This system initiates physiological changes like increased heart rate, dilated pupils, and the release of adrenaline, preparing the body to confront or escape the threat. The somatic nervous system (Choice A) controls voluntary movements, the parasympathetic nervous system (Choice B) is responsible for the 'rest and digest' response to promote relaxation and digestion, and the enteric nervous system (Choice D) regulates the gastrointestinal system. Therefore, they are not associated with the 'fight-or-flight' response.

5. Anya was paid by Company X to analyze dwindling honeybee populations in the Southwest. After measuring hive populations over several months, she noticed no patterns in the geographic distributions of the deaths after comparisons with local maps of interest. This supported her hypothesis, so she took samples of the honey and the bees from the hives and performed dozens of dissections to confirm her suspicions. Which of the following is the most likely hypothesis upon which this research was performed?

• A. Honeybees are being killed off, and their hives are destroyed by other extremely aggressive species of bees from the South.
• B. Honeybees are contracting parasites in large droves.
• C. Honeybees are so sensitive to certain pesticides that they die on contact.
• D. Honeybees die in larger numbers around cell phone towers.

Correct answer: B

Rationale: The most likely hypothesis based on the information provided is that honeybees are contracting parasites in large droves. Anya observed no geographic patterns in hive deaths and proceeded to analyze honey and bees for further investigation. This suggests that she suspected a widespread issue affecting multiple hives simultaneously, consistent with a scenario where honeybees are being infected by parasites in high numbers, leading to dwindling populations across different locations. The other choices can be eliminated because there is no mention of aggressive species of bees from the South, no evidence pointing to pesticide sensitivity as the cause, and no indication of a correlation with cell phone towers in the information provided.

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