Nursing Elites

1. Which of the following nerves has the longest axon in the human body?

• A. Dorsal root ganglion
• B. Laryngeal nerve
• C. Sciatic nerve
• D. None of the above

Correct answer: C

Rationale: The sciatic nerve contains the longest axon in the human body, extending from the lower back down the leg. This nerve is responsible for innervating the muscles of the lower limb. The dorsal root ganglion and laryngeal nerve do not possess axons as long as the sciatic nerve, making them incorrect choices. Therefore, the correct answer is C, the sciatic nerve.

2. Which of the following is a consequence of bone marrow failure?

• A. Seizures.
• B. Pancytopenia.
• C. Paraplegia.
• D. Pathologic fractures.

Correct answer: B

Rationale: The corrected question focuses on the consequence of bone marrow failure, which is pancytopenia. Bone marrow failure results in decreased production of red blood cells, white blood cells, and platelets, leading to pancytopenia. This condition manifests as fatigue, weakness, increased infection susceptibility, and bleeding tendencies. Paraplegia, seizures, and pathologic fractures are not typical outcomes of bone marrow failure. Paraplegia is associated with spinal cord injury, seizures with neurological disorders, and pathologic fractures with conditions like osteoporosis or bone tumors.

3. If the mass of an object remains constant and its velocity doubles, how does its momentum change?

• A. Momentum doubles
• B. Momentum halves
• C. Momentum quadruples
• D. Momentum remains the same

Correct answer: C

Rationale: Momentum is calculated as the product of an object's mass and its velocity. When the mass remains constant and the velocity doubles, the momentum will increase by a factor of 2 (doubling) due to the increase in velocity. Therefore, the momentum will quadruple (2 x 2 = 4) when the velocity doubles. This relationship between momentum and velocity showcases the direct proportionality of momentum to velocity, given a constant mass. Choices A, B, and D are incorrect. Momentum does not simply double or halve when the velocity doubles; it quadruples as it is directly proportional to the velocity. Hence, the correct answer is C, where momentum quadruples in this scenario.

4. What is the shape of the DNA molecule?

• A. Linear
• B. Circular
• C. Double helix
• D. Straight chain

Correct answer: C

Rationale: The correct answer is C: Double helix. The shape of the DNA molecule is a double helix, a structure first described by James Watson and Francis Crick in 1953. This shape consists of two strands twisted around each other in a spiral. The double helix structure allows DNA to be compactly stored within the cell nucleus and provides stability to the molecule. Options (A) Linear, (B) Circular, and (D) Straight chain are incorrect as they do not accurately represent the shape of the DNA molecule. DNA is not linear but rather forms a twisted double helix; it is not circular like a ring but has a spiral structure, and it is not a straight chain but a twisted ladder-like structure.

5. What is the 'lock-and-key' model?

• A. Protein folding
• B. Enzyme-substrate interaction
• C. Muscle contraction
• D. Blood clotting

Correct answer: B

Rationale: The 'lock-and-key' model describes the specificity of the interaction between enzymes and their substrates. In this model, the enzyme's active site acts like a lock that can only be opened by the specific substrate molecule, which serves as the key. This specific binding ensures that enzymes catalyze particular reactions and do not interact with other molecules indiscriminately. Protein folding (option A) is the process by which a protein attains its functional three-dimensional structure but is not directly related to the lock-and-key model. Muscle contraction (option C) and blood clotting (option D) are complex biological processes but are not directly associated with the lock-and-key model of enzyme-substrate interaction.

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