Nursing Elites

1. What is the primary purpose of control rods within a nuclear reactor?

• A. Reflecting neutrons back into the core
• B. Absorbing excess neutrons to control criticality
• C. Moderating the velocity of neutrons
• D. All of the above

Correct answer: B

Rationale: The primary purpose of control rods in a nuclear reactor is to absorb excess neutrons to control criticality. When inserted into the reactor core, control rods absorb neutrons, reducing the number available for sustaining the fission chain reaction. This action allows operators to manage the reactor power levels and prevent overheating or runaway reactions. Reflecting neutrons back into the core and moderating neutron velocity are not the primary functions of control rods in a nuclear reactor. Choice A is incorrect because control rods do not reflect neutrons back into the core but absorb them. Choice C is incorrect as the moderation of neutron velocity is typically achieved by other materials like a moderator (e.g., water, graphite) rather than control rods. Choice D is incorrect as control rods do not reflect neutrons or moderate neutron velocity, making it an incorrect option.

2. Which of the following statements is true about Noble gases?

• A. They are non-reactive.
• B. They are highly reactive.
• C. They have 8 valence electrons.
• D. They have 7 valence electrons.

Correct answer: A

Rationale: The correct answer is A: Noble gases are non-reactive because they have a full valence shell with 8 electrons, making them stable and unlikely to form chemical bonds with other elements. Choice B is incorrect because Noble gases are known for their inertness and lack of reactivity. Choice C is incorrect because Noble gases have 8 valence electrons, which is a key characteristic that contributes to their stability. Choice D is incorrect because Noble gases have 8 valence electrons, not 7.

3. What is the major difference between somatic and germline mutations?

• A. Somatic mutations usually benefit the individual while germline mutations usually harm them.
• B. Since germline mutations only affect one cell, they are less noticeable than the rapidly dividing somatic cells.
• C. Somatic mutations are not expressed for several generations, but germline mutations are expressed immediately.
• D. Germline mutations are usually inherited while somatic mutations will affect only the individual.

Correct answer: D

Rationale: The major difference between somatic and germline mutations is that germline mutations are usually inherited and can be passed on to offspring, while somatic mutations occur in non-reproductive cells and only affect the individual in which they occur. This means that germline mutations have the potential to be present in future generations, while somatic mutations do not.

4. What is the name of the regulatory region in a gene that controls its expression?

• A. Exon
• B. Intron
• C. Promoter
• D. Enhancer

Correct answer: C

Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression. B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression. C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression. D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter. Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.

5. What is the formula to calculate work?

• A. Work = Force × Distance
• B. Work = Mass × Velocity
• C. Work = Power × Time
• D. Work = Energy ÷ Time

Correct answer: A

Rationale: Work is defined as the product of the force applied to an object and the distance over which the force is applied. The formula to calculate work is represented by Work = Force × Distance, where force is the applied force on an object and distance is the displacement over which the force is applied. Therefore, the correct formula to calculate work is Work = Force × Distance. Choice B, 'Work = Mass × Velocity,' is incorrect because work involves force and distance, not mass and velocity. Choice C, 'Work = Power × Time,' is incorrect because work is not directly calculated using power and time. Choice D, 'Work = Energy ÷ Time,' is incorrect because work is not typically calculated by dividing energy by time; rather, it involves the product of force and distance.

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