Nursing Elites

1. Which feedback loops are less common and sometimes harmful because they enhance stimuli rather than inhibit them?

• A. Negative feedback loop
• B. Positive feedback loop
• C. Inhibitory feedback loop
• D. Stimulating feedback loop

Correct answer: B

Rationale: Correct. Positive feedback loops enhance or amplify changes, which can sometimes be harmful as they drive processes further from equilibrium. In contrast, negative feedback loops work to counteract deviations from a set point, promoting stability. Choice A, 'Negative feedback loop,' is incorrect because negative feedback loops inhibit or reduce changes, promoting stability. Choice C, 'Inhibitory feedback loop,' is incorrect as it is synonymous with negative feedback loops. Choice D, 'Stimulating feedback loop,' is incorrect as it inaccurately describes the nature of positive feedback loops.

2. What is the breakdown product of ATP (adenosine triphosphate) that provides energy for muscle contraction?

• A. Glucose
• B. Creatine phosphate
• C. ADP (adenosine diphosphate)
• D. Lactic acid

Correct answer: C

Rationale: ADP (adenosine diphosphate) is the correct breakdown product of ATP that provides energy for muscle contraction. When ATP is hydrolyzed to ADP, energy is released and utilized by the muscles for various cellular processes, including muscle contraction. Glucose serves as an energy source but is not the direct breakdown product of ATP for muscle contraction. Creatine phosphate plays a role in energy storage and transfer, but it is not the immediate breakdown product of ATP. Lactic acid is produced during anaerobic metabolism and is not the direct provider of energy for muscle contraction.

3. Which part of the neuron insulates and speeds up the transmission of nerve impulses along the axon?

• A. Dendrite
• B. Myelin sheath
• C. Synapse
• D. Cell body

Correct answer: B

Rationale: The myelin sheath is a fatty layer that surrounds the axon of a neuron, providing insulation and speeding up the transmission of nerve impulses. This insulation helps prevent the loss of electrical signals as they travel along the axon, allowing for faster and more efficient communication within the nervous system. Dendrites are branching extensions of a neuron that receive signals from other neurons, the synapse is the junction between two neurons where communication occurs, and the cell body contains the nucleus and organelles of the neuron, but none of these structures provide insulation for the transmission of nerve impulses along the axon.

4. After the Industrial Revolution, the population of peppered moths in England shifted towards more dark moths. This is an example of:

• A. Artificial selection (selective breeding by humans for desired traits)
• B. Natural selection acting on pre-existing variation
• C. Punctuated equilibrium (rapid bursts of evolution)
• D. Lamarckism (inheritance of acquired characteristics)

Correct answer: B

Rationale: The shift in the peppered moth population towards more dark moths in England after the Industrial Revolution exemplifies natural selection acting on pre-existing variation. Initially, light-colored moths were well-camouflaged against lichen-covered tree trunks, but with industrial pollution darkening the tree trunks, dark-colored moths gained a survival advantage. This change reflects how the environment favored dark moths over light ones, illustrating natural selection. The process illustrates how organisms with traits advantageous in a changing environment are more likely to survive and reproduce, leading to the prevalence of those traits in the population over time. The choices of artificial selection (A), punctuated equilibrium (C), and Lamarckism (D) are not applicable in this scenario. Artificial selection involves intentional breeding by humans, punctuated equilibrium refers to rapid bursts of evolution followed by periods of stability, and Lamarckism suggests the inheritance of acquired characteristics, none of which align with the observed shift in moth populations based on environmental changes.

5. When is work done by a force on an object?

• A. Only when the object moves in the direction of the force
• B. Only when the object moves against the force
• C. Only when the object moves vertically
• D. Only when the force is applied for a specific duration

Correct answer: A

Rationale: Work is done by a force on an object when the object moves in the direction of the force. This is because work is defined as the product of the force applied to an object and the distance over which the force is applied. When the object moves in the direction of the force, the force contributes to the displacement of the object, resulting in work being done. If the object moves perpendicular to the force, no work is done because the force does not contribute to the displacement. Moving against the force also results in work being done as the force is causing the displacement. The vertical movement of the object does not determine whether work is done; it is the alignment of the force with the object's displacement that matters. The duration of force application does not impact whether work is done; as long as the force causes the object to move in its direction, work is being done.

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