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: 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.

2. Sunscreen protects the skin from harmful ultraviolet (UV) rays by

• A. Reflecting UV rays away from the skin
• B. Absorbing UV rays and converting them to heat
• C. Blocking UV rays completely
• D. Stimulating melanin production

Correct answer: B

Rationale: The correct answer is B: Absorbing UV rays and converting them to heat. Sunscreen contains ingredients that act as filters to absorb UV radiation before it reaches the skin. These filters then convert the UV rays into a less harmful form of energy, usually heat, which is then released from the body. This process helps prevent UV radiation from damaging the skin cells and causing sunburn or long-term skin damage. Reflecting UV rays away from the skin (A) and blocking UV rays completely (C) are not accurate functions of sunscreen. Additionally, stimulating melanin production (D) is not a direct way in which sunscreen protects the skin from UV rays.

3. Antibiotic resistance in bacteria is an example of:

• A. Convergent evolution
• B. Divergent evolution
• C. Microevolution
• D. Macroevolution

Correct answer: C

Rationale: Rationale: - Convergent evolution (option A) refers to the process by which different species evolve similar traits independently in response to similar environmental pressures. Antibiotic resistance in bacteria does not involve different species evolving similar traits. - Divergent evolution (option B) refers to the process by which two or more related species become more dissimilar over time. Antibiotic resistance in bacteria does not involve related species becoming more dissimilar. - Microevolution (option C) refers to changes in allele frequencies within a population over a relatively short period of time. Antibiotic resistance in bacteria is a classic example of microevolution, where bacteria evolve resistance to antibiotics through the natural selection of pre-existing resistant strains. - Macroevolution (option D) refers to large-scale evolutionary changes that result in the formation of new species or higher taxonomic groups. Antibiotic resistance in bacteria does not involve

4. The fossil record shows that dinosaurs with feathers existed millions of years before birds. This is evidence for

• A. Convergent evolution (unrelated organisms evolving similar traits)
• B. Divergent evolution (related organisms evolving different traits)
• C. Coevolution (two species influencing each other's evolution)
• D. The extinction of dinosaurs due to an asteroid impact

Correct answer: A

Rationale: Rationale: The fossil record indicating that dinosaurs had feathers before birds suggests convergent evolution. Convergent evolution occurs when unrelated organisms independently evolve similar traits to adapt to similar environmental pressures. In this case, both dinosaurs and birds developed feathers for flight or insulation purposes, even though they are not closely related. This evidence supports the concept of convergent evolution rather than divergent evolution, coevolution, or the extinction of dinosaurs due to an asteroid impact.

5. The process of splitting a heavy nucleus into smaller nuclei, releasing a vast amount of energy, is called:

• A. Nuclear fusion
• B. Nuclear fission
• C. Radioactive decay
• D. Chain reaction

Correct answer: B

Rationale: Rationale: Nuclear fission is the process of splitting a heavy nucleus into smaller nuclei, releasing a vast amount of energy. This process is commonly used in nuclear power plants and nuclear weapons. A) Nuclear fusion is the process of combining two light nuclei to form a heavier nucleus, releasing energy in the process. This process powers the sun and other stars. C) Radioactive decay is the process by which an unstable atomic nucleus loses energy by emitting radiation. D) Chain reaction is a self-sustaining reaction in which the products of one reaction event stimulate further reaction events. This can occur in both nuclear fission and nuclear fusion reactions.

6. Melatonin is a hormone produced by the pineal gland. What is its primary function?

• A. Regulate blood pressure
• B. Stimulate the digestive system
• C. Control sleep-wake cycles
• D. Maintain bone density

Correct answer: C

Rationale: The correct answer is C: 'Control sleep-wake cycles.' Melatonin is a hormone that plays a key role in regulating the body's sleep-wake cycle, also known as the circadian rhythm. The pineal gland releases melatonin in response to darkness, helping to signal to the body that it is time to sleep. By influencing the timing and quality of sleep, melatonin helps maintain a healthy sleep pattern and overall well-being. While blood pressure, digestive system stimulation, and bone density are important functions in the body, melatonin's primary function is to regulate the sleep-wake cycle.

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